Reaction Process: PathBank:SMP0063662

Retinol Metabolism related metabolites

find 30 related metabolites which is associated with chemical reaction(pathway) Retinol Metabolism

NAD + Vitamin A + Water ⟶ NADH + all-trans-Retinoic acid

beta-Carotene

1,3,3-trimethyl-2-[(1E,3E,5E,7E,9E,11E,13E,15E,17E)-3,7,12,16-tetramethyl-18-(2,6,6-trimethylcyclohex-1-en-1-yl)octadeca-1,3,5,7,9,11,13,15,17-nonaen-1-yl]cyclohex-1-ene

C40H56 (536.4381776)


Beta-carotene is a cyclic carotene obtained by dimerisation of all-trans-retinol. A strongly-coloured red-orange pigment abundant in plants and fruit and the most active and important provitamin A carotenoid. It has a role as a biological pigment, a provitamin A, a plant metabolite, a human metabolite, a mouse metabolite, a cofactor, a ferroptosis inhibitor and an antioxidant. It is a cyclic carotene and a carotenoid beta-end derivative. Beta-carotene, with the molecular formula C40H56, belongs to the group of carotenoids consisting of isoprene units. The presence of long chains of conjugated double bonds donates beta-carotene with specific colors. It is the most abundant form of carotenoid and it is a precursor of the vitamin A. Beta-carotene is composed of two retinyl groups. It is an antioxidant that can be found in yellow, orange and green leafy vegetables and fruits. Under the FDA, beta-carotene is considered as a generally recognized as safe substance (GRAS). Beta-Carotene is a natural product found in Epicoccum nigrum, Lonicera japonica, and other organisms with data available. Beta-Carotene is a naturally-occurring retinol (vitamin A) precursor obtained from certain fruits and vegetables with potential antineoplastic and chemopreventive activities. As an anti-oxidant, beta carotene inhibits free-radical damage to DNA. This agent also induces cell differentiation and apoptosis of some tumor cell types, particularly in early stages of tumorigenesis, and enhances immune system activity by stimulating the release of natural killer cells, lymphocytes, and monocytes. (NCI04) beta-Carotene is a metabolite found in or produced by Saccharomyces cerevisiae. A carotenoid that is a precursor of VITAMIN A. Beta carotene is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC). See also: Lycopene (part of); Broccoli (part of); Lycium barbarum fruit (part of). Beta-Carotene belongs to the class of organic compounds known as carotenes. These are a type of polyunsaturated hydrocarbon molecules containing eight consecutive isoprene units. Carotenes are characterized by the presence of two end-groups (mostly cyclohexene rings, but also cyclopentene rings or acyclic groups) linked by a long branched alkyl chain. Beta-carotene is therefore considered to be an isoprenoid lipid molecule. Beta-carotene is a strongly coloured red-orange pigment abundant in fungi, plants, and fruits. It is synthesized biochemically from eight isoprene units and therefore has 40 carbons. Among the carotenes, beta-carotene is distinguished by having beta-rings at both ends of the molecule. Beta-Carotene is biosynthesized from geranylgeranyl pyrophosphate. It is the most common form of carotene in plants. In nature, Beta-carotene is a precursor (inactive form) to vitamin A. Vitamin A is produed via the action of beta-carotene 15,15-monooxygenase on carotenes. In mammals, carotenoid absorption is restricted to the duodenum of the small intestine and dependent on a class B scavenger receptor (SR-B1) membrane protein, which is also responsible for the absorption of vitamin E. One molecule of beta-carotene can be cleaved by the intestinal enzyme Beta-Beta-carotene 15,15-monooxygenase into two molecules of vitamin A. Beta-Carotene contributes to the orange color of many different fruits and vegetables. Vietnamese gac and crude palm oil are particularly rich sources, as are yellow and orange fruits, such as cantaloupe, mangoes, pumpkin, and papayas, and orange root vegetables such as carrots and sweet potatoes. Excess beta-carotene is predominantly stored in the fat tissues of the body. The most common side effect of excessive beta-carotene consumption is carotenodermia, a physically harmless condition that presents as a conspicuous orange skin tint arising from deposition of the carotenoid in the outermost layer of the epidermis. Yellow food colour, dietary supplement, nutrient, Vitamin A precursor. Nutriceutical with antioxidation props. beta-Carotene is found in many foods, some of which are summer savory, gram bean, sunburst squash (pattypan squash), and other bread product. A cyclic carotene obtained by dimerisation of all-trans-retinol. A strongly-coloured red-orange pigment abundant in plants and fruit and the most active and important provitamin A carotenoid. D - Dermatologicals > D02 - Emollients and protectives > D02B - Protectives against uv-radiation > D02BB - Protectives against uv-radiation for systemic use A - Alimentary tract and metabolism > A11 - Vitamins > A11C - Vitamin a and d, incl. combinations of the two > A11CA - Vitamin a, plain D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D018977 - Micronutrients > D014815 - Vitamins > D000072664 - Provitamins

   

Coenzyme A

{[(2R,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-4-hydroxy-2-({[hydroxy({hydroxy[(3R)-3-hydroxy-2,2-dimethyl-3-({2-[(2-sulfanylethyl)carbamoyl]ethyl}carbamoyl)propoxy]phosphoryl}oxy)phosphoryl]oxy}methyl)oxolan-3-yl]oxy}phosphonic acid

C21H36N7O16P3S (767.1152046)


Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme notable for its role in the synthesis and oxidization of fatty acids and the oxidation of pyruvate in the citric acid cycle. It is adapted from beta-mercaptoethylamine, panthothenate, and adenosine triphosphate. It is also a parent compound for other transformation products, including but not limited to, phenylglyoxylyl-CoA, tetracosanoyl-CoA, and 6-hydroxyhex-3-enoyl-CoA. Coenzyme A is synthesized in a five-step process from pantothenate and cysteine. In the first step pantothenate (vitamin B5) is phosphorylated to 4-phosphopantothenate by the enzyme pantothenate kinase (PanK, CoaA, CoaX). In the second step, a cysteine is added to 4-phosphopantothenate by the enzyme phosphopantothenoylcysteine synthetase (PPC-DC, CoaB) to form 4-phospho-N-pantothenoylcysteine (PPC). In the third step, PPC is decarboxylated to 4-phosphopantetheine by phosphopantothenoylcysteine decarboxylase (CoaC). In the fourth step, 4-phosphopantetheine is adenylylated to form dephospho-CoA by the enzyme phosphopantetheine adenylyl transferase (CoaD). Finally, dephospho-CoA is phosphorylated using ATP to coenzyme A by the enzyme dephosphocoenzyme A kinase (CoaE). Since coenzyme A is, in chemical terms, a thiol, it can react with carboxylic acids to form thioesters, thus functioning as an acyl group carrier. CoA assists in transferring fatty acids from the cytoplasm to the mitochondria. A molecule of coenzyme A carrying an acetyl group is also referred to as acetyl-CoA. When it is not attached to an acyl group, it is usually referred to as CoASH or HSCoA. Coenzyme A is also the source of the phosphopantetheine group that is added as a prosthetic group to proteins such as acyl carrier proteins and formyltetrahydrofolate dehydrogenase. Acetyl-CoA is an important molecule itself. It is the precursor to HMG CoA which is a vital component in cholesterol and ketone synthesis. Furthermore, it contributes an acetyl group to choline to produce acetylcholine in a reaction catalysed by choline acetyltransferase. Its main task is conveying the carbon atoms within the acetyl group to the citric acid cycle to be oxidized for energy production (Wikipedia). Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidization of fatty acids, and the oxidation of pyruvate in the citric acid cycle. It is adapted from beta-mercaptoethylamine, panthothenate and adenosine triphosphate. Acetyl-CoA is an important molecule itself. It is the precursor to HMG CoA, which is a vital component in cholesterol and ketone synthesis. Furthermore, it contributes an acetyl group to choline to produce acetylcholine, in a reaction catalysed by choline acetyltransferase. Its main task is conveying the carbon atoms within the acetyl group to the citric acid cycle to be oxidized for energy production. -- Wikipedia [HMDB]. Coenzyme A is found in many foods, some of which are grape, cowpea, pili nut, and summer savory. Coenzyme A (CoASH) is a ubiquitous and essential cofactor, which is an acyl group carrier and carbonyl-activating group for the citric acid cycle and fatty acid metabolism. Coenzyme A plays a central role in the oxidation of pyruvate in the citric acid cycle and the metabolism of carboxylic acids, including short- and long-chain fatty acids[1]. Coenzyme A (CoASH) is a ubiquitous and essential cofactor, which is an acyl group carrier and carbonyl-activating group for the citric acid cycle and fatty acid metabolism. Coenzyme A plays a central role in the oxidation of pyruvate in the citric acid cycle and the metabolism of carboxylic acids, including short- and long-chain fatty acids[1]. Coenzyme A, a ubiquitous essential cofactor, is an acyl group carrier and carbonyl-activating group for the citric acid cycle and fatty acid metabolism. Coenzyme A plays a central role in the metabolism of carboxylic acids, including short- and long-chain fatty acids. Coenzyme A. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=85-61-0 (retrieved 2024-10-17) (CAS RN: 85-61-0). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).

   

all-trans-Retinoic acid

(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenoic acid

C20H28O2 (300.2089188)


all-trans-Retinoic acid is an isomer of retinoic acid, the oxidized form of vitamin A. Retinoic acid functions in determining position along embryonic anterior/posterior axis in chordates. It acts through Hox genes, which ultimately controls anterior/posterior patterning in early developmental stages (PMID:17495912). It is an important regulator of gene expression during growth and development, and in neoplasms. As a drug, all-trans-retinoic acid is known as tretinoin. Tretinoin is derived from maternal vitamin A and is essential for normal growth and embryonic development. An excess of tretinoin can be teratogenic. Tretinoin is used in the treatment of psoriasis, acne vulgaris, and several other skin diseases. It has also been approved for use in promyelocytic leukemia (leukemia, promyelocytic, acute). Retinoic acid is the oxidized form of Vitamin A. It functions in determining position along embryonic anterior/posterior axis in chordates. It acts through Hox genes, which ultimately controls anterior/posterior patterning in early developmental stages (PMID: 17495912). It is an important regulator of gene expression during growth and development, and in neoplasms. Tretinoin, also known as retinoic acid and derived from maternal vitamin A, is essential for normal growth and embryonic development. An excess of tretinoin can be teratogenic. It is used in the treatment of psoriasis; acne vulgaris; and several other skin diseases. It has also been approved for use in promyelocytic leukemia (leukemia, promyelocytic, acute). [HMDB] L - Antineoplastic and immunomodulating agents > L01 - Antineoplastic agents > L01X - Other antineoplastic agents > L01XF - Retinoids for cancer treatment D - Dermatologicals > D10 - Anti-acne preparations > D10A - Anti-acne preparations for topical use > D10AD - Retinoids for topical use in acne C274 - Antineoplastic Agent > C2122 - Cell Differentiating Agent > C1934 - Differentiation Inducer C274 - Antineoplastic Agent > C163758 - Targeted Therapy Agent > C804 - Retinoic Acid Agent Acquisition and generation of the data is financially supported in part by CREST/JST. C308 - Immunotherapeutic Agent > C129820 - Antineoplastic Immunomodulating Agent D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D003879 - Dermatologic Agents > D007641 - Keratolytic Agents D000970 - Antineoplastic Agents Retinoic acid is a metabolite of vitamin A that plays important roles in cell growth, differentiation, and organogenesis. Retinoic acid is a natural agonist of RAR nuclear receptors, with IC50s of 14 nM for RARα/β/γ. Retinoic acid bind to PPARβ/δ with Kd of 17 nM. Retinoic acid acts as an inhibitor of transcription factor Nrf2 through activation of retinoic acid receptor alpha. Retinoic acid is a metabolite of vitamin A that plays important roles in cell growth, differentiation, and organogenesis. Retinoic acid is a natural agonist of RAR nuclear receptors, with IC50s of 14 nM for RARα/β/γ. Retinoic acid bind to PPARβ/δ with Kd of 17 nM. Retinoic acid acts as an inhibitor of transcription factor Nrf2 through activation of retinoic acid receptor alpha. Retinoic acid is a metabolite of vitamin A that plays important roles in cell growth, differentiation, and organogenesis. Retinoic acid is a natural agonist of RAR nuclear receptors, with IC50s of 14 nM for RARα/β/γ. Retinoic acid bind to PPARβ/δ with Kd of 17 nM. Retinoic acid acts as an inhibitor of transcription factor Nrf2 through activation of retinoic acid receptor alpha.

   

Retinal

(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenal

C20H28O (284.2140038)


A carotenoid constituent of visual pigments. It is the oxidized form of retinol which functions as the active component of the visual cycle. It is bound to the protein opsin forming the complex rhodopsin. When stimulated by visible light, the retinal component of the rhodopsin complex undergoes isomerization at the 11-position of the double bond to the cis-form; this is reversed in "dark" reactions to return to the native trans-configuration. [HMDB]. Retinal is found in many foods, some of which are flaxseed, pepper (c. baccatum), climbing bean, and other soy product. Retinal is a carotenoid constituent of visual pigments. It is the oxidized form of retinol which functions as the active component of the visual cycle. It is bound to the protein opsin forming the complex rhodopsin. When stimulated by visible light, the retinal component of the rhodopsin complex undergoes isomerization at the 11-position of the double bond to the cis-form; this is reversed in "dark" reactions to return to the native trans-configuration. D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids CONFIDENCE standard compound; INTERNAL_ID 142

   

Acetyl-CoA

{[(2R,3S,4R,5R)-2-({[({[(3R)-3-[(2-{[2-(acetylsulfanyl)ethyl]carbamoyl}ethyl)carbamoyl]-3-hydroxy-2,2-dimethylpropoxy](hydroxy)phosphoryl}oxy)(hydroxy)phosphoryl]oxy}methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxyoxolan-3-yl]oxy}phosphonic acid

C23H38N7O17P3S (809.1257688000001)


The main function of coenzyme A is to carry acyl groups (such as the acetyl group) or thioesters. Acetyl-CoA is an important molecule itself. It is the precursor to HMG CoA, which is a vital component in cholesterol and ketone synthesis. (wikipedia). acetyl CoA participates in the biosynthesis of fatty acids and sterols, in the oxidation of fatty acids and in the metabolism of many amino acids. It also acts as a biological acetylating agent. The main function of coenzyme A is to carry acyl groups (such as the acetyl group) or thioesters. Acetyl-CoA is an important molecule itself. It is the precursor to HMG CoA, which is a vital component in cholesterol and ketone synthesis. (wikipedia)

   

Nadide

beta-Nicotinamide adenine dinucleotide hydrate

[C21H28N7O14P2]+ (664.1169428000001)


[Spectral] NAD+ (exact mass = 663.10912) and 3,4-Dihydroxy-L-phenylalanine (exact mass = 197.06881) and Cytidine (exact mass = 243.08552) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. [Spectral] NAD+ (exact mass = 663.10912) and NADP+ (exact mass = 743.07545) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. COVID info from COVID-19 Disease Map Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

NADP+

beta-Nicotinamide adenine dinucleotide phosphate oxidized form sodium salt hydrate

[C21H29N7O17P3]+ (744.0832754)


[Spectral] NADP+ (exact mass = 743.07545) and NAD+ (exact mass = 663.10912) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. COVID info from COVID-19 Disease Map Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

1,4-Dihydronicotinamide adenine dinucleotide

Dihydronicotinamide-adenine dinucleotide

C21H29N7O14P2 (665.1247674)


Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen) respectively. NADH is the reduced form of NAD+, and NAD+ is the oxidized form of NADH. NAD (or nicotinamide adenine dinucleotide) is used extensively in glycolysis and the citric acid cycle of cellular respiration. The reducing potential stored in NADH can be either converted into ATP through the electron transport chain or used for anabolic metabolism. ATP "energy" is necessary for an organism to live. Green plants obtain ATP through photosynthesis, while other organisms obtain it via cellular respiration. NAD is a coenzyme composed of ribosylnicotinamide 5-diphosphate coupled to adenosine 5-phosphate by a pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). NADP is formed through the addition of a phosphate group to the 2 position of the adenosyl nucleotide through an ester linkage. NADH is the reduced form of NAD+, and NAD+ is the oxidized form of NADH, A coenzyme composed of ribosylnicotinamide 5-diphosphate coupled to adenosine 5-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). It forms NADP with the addition of a phosphate group to the 2 position of the adenosyl nucleotide through an ester linkage.(Dorland, 27th ed) [HMDB]. NADH is found in many foods, some of which are dill, ohelo berry, fox grape, and black-eyed pea. Acquisition and generation of the data is financially supported in part by CREST/JST. COVID info from COVID-19 Disease Map Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

Retinol(Vitamin A)

3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol, (all-e)-isomer

C20H30O (286.229653)


Vitamin A (retinol) is a yellow fat-soluble, antioxidant vitamin important in vision and bone growth. It belongs to the family of chemical compounds known as retinoids. Retinol is ingested in a precursor form; animal sources (milk and eggs) contain retinyl esters, whereas plants (carrots, spinach) contain pro-vitamin A carotenoids. Hydrolysis of retinyl esters results in retinol while pro-vitamin A carotenoids can be cleaved to produce retinal. Retinal, also known as retinaldehyde, can be reversibly reduced to produce retinol or it can be irreversibly oxidized to produce retinoic acid. Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of carotenoids found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products. Retinyl esters from animal-sourced foods (or synthesized for dietary supplements for humans and domesticated animals) are acted upon by retinyl ester hydrolases in the lumen of the small intestine to release free retinol. Retinol enters intestinal absorptive cells by passive diffusion. Absorption efficiency is in the range of 70 to 90\%. Humans are at risk for acute or chronic vitamin A toxicity because there are no mechanisms to suppress absorption or excrete the excess in urine.[5] Within the cell, retinol is there bound to retinol binding protein 2 (RBP2). It is then enzymatically re-esterified by the action of lecithin retinol acyltransferase and incorporated into chylomicrons that are secreted into the lymphatic system. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1). The protein is upregulated in times of vitamin A deficiency. If vitamin A status is in the normal range, SCARB1 is downregulated, reducing absorption.[6] Also downregulated is the enzyme beta-carotene 15,15'-dioxygenase (formerly known as beta-carotene 15,15'-monooxygenase) coded for by the BCMO1 gene, responsible for symmetrically cleaving β-carotene into retinal.[8] Absorbed β-carotene is either incorporated as such into chylomicrons or first converted to retinal and then retinol, bound to RBP2. After a meal, roughly two-thirds of the chylomicrons are taken up by the liver with the remainder delivered to peripheral tissues. Peripheral tissues also can convert chylomicron β-carotene to retinol.[6][15] The capacity to store retinol in the liver means that well-nourished humans can go months on a vitamin A deficient diet without manifesting signs and symptoms of deficiency. Two liver cell types are responsible for storage and release: hepatocytes and hepatic stellate cells (HSCs). Hepatocytes take up the lipid-rich chylomicrons, bind retinol to retinol-binding protein 4 (RBP4), and transfer the retinol-RBP4 to HSCs for storage in lipid droplets as retinyl esters. Mobilization reverses the process: retinyl ester hydrolase releases free retinol which is transferred to hepatocytes, bound to RBP4, and put into blood circulation. Other than either after a meal or when consumption of large amounts exceeds liver storage capacity, more than 95\% of retinol in circulation is bound to RBP4.[15] Vitamin A is a fat-soluble vitamin, hence an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin (precursor) carotenoids, most notably beta-carotene.[3][4][5][6] Vitamin A has multiple functions: essential in embryo development for growth, maintaining the immune system, and healthy vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.[7] Vitamin A occurs as two principal forms in foods: A) retinol, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids alpha-carotene, β-carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that function as provitamin A in herbivore and omnivore animals which possess the enzymes that cleave and convert provitamin carotenoids to retinal and then to retinol.[8] Some carnivore species lack this enzyme. The other carotenoids have no vitamin activity.[6] Dietary retinol is absorbed from the digestive tract via passive diffusion. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1), which is upregulated in times of vitamin A deficiency.[6] Storage of retinol is in lipid droplets in the liver. A high capacity for long-term storage of retinol means that well-nourished humans can go months on a vitamin A- and β-carotene-deficient diet, while maintaining blood levels in the normal range.[4] Only when the liver stores are nearly depleted will signs and symptoms of deficiency show.[4] Retinol is reversibly converted to retinal, then irreversibly to retinoic acid, which activates hundreds of genes.[9] Vitamin A deficiency is common in developing countries, especially in Sub-Saharan Africa and Southeast Asia. Deficiency can occur at any age but is most common in pre-school age children and pregnant women, the latter due to a need to transfer retinol to the fetus. Vitamin A deficiency is estimated to affect approximately one-third of children under the age of five around the world, resulting in hundreds of thousands of cases of blindness and deaths from childhood diseases because of immune system failure.[10] Reversible night blindness is an early indicator of low vitamin A status. Plasma retinol is used as a biomarker to confirm vitamin A deficiency. Breast milk retinol can indicate a deficiency in nursing mothers. Neither of these measures indicates the status of liver reserves.[6] The European Union and various countries have set recommendations for dietary intake, and upper limits for safe intake. Vitamin A toxicity also referred to as hypervitaminosis A, occurs when there is too much vitamin A accumulating in the body. Symptoms may include nervous system effects, liver abnormalities, fatigue, muscle weakness, bone and skin changes, and others. The adverse effects of both acute and chronic toxicity are reversed after consumption of high dose supplements is stopped.[6]

   

4-Oxoretinol

3-[(1E,3E,5E,7E)-9-hydroxy-3,7-dimethylnona-1,3,5,7-tetraen-1-yl]-2,4,4-trimethylcyclohex-2-en-1-one

C20H28O2 (300.2089188)


4-oxo-retinol, a metabolite of retinol synthesized in mouse embryonal carcinoma F9 cells,is active in inducing differentiation of these cells. It also functions as a ligand of retinoic acid receptors and a transcriptional activator of reporter. genes.[PMID: 9110564]. 4-Oxoretinol is a metabolite of retinol in the human promyelocytic leukemia cell line NB4 which induces cell growth arrest and granulocytic differentiation.[PMID: 9581846]. 4-oxo-retinol, a metabolite of retinol synthesized in mouse embryonal carcinoma F9 cells,is active in inducing differentiation of these cells. It also functions as a ligand of retinoic acid receptors and a transcriptional activator of reporter D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

All-trans-13,14-dihydroretinol

(4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-4,6,8-trien-1-ol

C20H32O (288.24530219999997)


All-trans-13,14-dihydroretinol is involved in the retinol metabolism pathway. In this pathway, all-trans-13,14-dihydroretinol and an acceptor molecule is reversibly converted to retinol (vitamin A) plus reduced acceptor via the enzyme all-trans-retinol 13,14-reductase (EC 1.3.99.23). (KEGG) [HMDB] All-trans-13,14-dihydroretinol is involved in the retinol metabolism pathway. In this pathway, all-trans-13,14-dihydroretinol and an acceptor molecule is reversibly converted to retinol (vitamin A) plus reduced acceptor via the enzyme all-trans-retinol 13,14-reductase (EC 1.3.99.23). (KEGG). D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

Retinoyl b-glucuronide

1-O-[(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenoyl]-β-D-glucopyranuronic acid O(15)-[(2S,3R,4S,5S,6S)-6-carboxy-3,4,5-trihydroxytetrahydro-2H-pyran-2-yl]retinoic acid

C26H36O8 (476.2410056)


Retinoyl beta-glucuronide is a naturally occurring, biologically active metabolite of vitamin A. Although retinoyl beta-glucuronide is regarded as a detoxification product of retinoic acid, it plays several roles in the functions of vitamin A. It can serve as a source of retinoic acid, and it may be a vehicle for transport of retinoic acid to target tissues. Topically applied retinoyl beta-glucuronide is comparable in efficacy to retinoic acid in the treatment of acne in humans, without the same side effects. Retinoyl beta-glucuronide may or may not be teratogenic, depending on the mode of administration and the species in which it is used. It may be a valuable therapeutic compound for the treatment of skin disorders and certain types of cancers. [HMDB] Retinoyl beta-glucuronide is a naturally occurring, biologically active metabolite of vitamin A. Although retinoyl beta-glucuronide is regarded as a detoxification product of retinoic acid, it plays several roles in the functions of vitamin A. It can serve as a source of retinoic acid, and it may be a vehicle for transport of retinoic acid to target tissues. Topically applied retinoyl beta-glucuronide is comparable in efficacy to retinoic acid in the treatment of acne in humans, without the same side effects. Retinoyl beta-glucuronide may or may not be teratogenic, depending on the mode of administration and the species in which it is used. It may be a valuable therapeutic compound for the treatment of skin disorders and certain types of cancers. D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

Water

oxidane

H2O (18.0105642)


Water is a chemical substance that is essential to all known forms of life. It appears colorless to the naked eye in small quantities, though it is actually slightly blue in color. It covers 71\\% of Earths surface. Current estimates suggest that there are 1.4 billion cubic kilometers (330 million m3) of it available on Earth, and it exists in many forms. It appears mostly in the oceans (saltwater) and polar ice caps, but it is also present as clouds, rain water, rivers, freshwater aquifers, lakes, and sea ice. Water in these bodies perpetually moves through a cycle of evaporation, precipitation, and runoff to the sea. Clean water is essential to human life. In many parts of the world, it is in short supply. From a biological standpoint, water has many distinct properties that are critical for the proliferation of life that set it apart from other substances. It carries out this role by allowing organic compounds to react in ways that ultimately allow replication. All known forms of life depend on water. Water is vital both as a solvent in which many of the bodys solutes dissolve and as an essential part of many metabolic processes within the body. Metabolism is the sum total of anabolism and catabolism. In anabolism, water is removed from molecules (through energy requiring enzymatic chemical reactions) in order to grow larger molecules (e.g. starches, triglycerides and proteins for storage of fuels and information). In catabolism, water is used to break bonds in order to generate smaller molecules (e.g. glucose, fatty acids and amino acids to be used for fuels for energy use or other purposes). Water is thus essential and central to these metabolic processes. Water is also central to photosynthesis and respiration. Photosynthetic cells use the suns energy to split off waters hydrogen from oxygen. Hydrogen is combined with CO2 (absorbed from air or water) to form glucose and release oxygen. All living cells use such fuels and oxidize the hydrogen and carbon to capture the suns energy and reform water and CO2 in the process (cellular respiration). Water is also central to acid-base neutrality and enzyme function. An acid, a hydrogen ion (H+, that is, a proton) donor, can be neutralized by a base, a proton acceptor such as hydroxide ion (OH-) to form water. Water is considered to be neutral, with a pH (the negative log of the hydrogen ion concentration) of 7. Acids have pH values less than 7 while bases have values greater than 7. Stomach acid (HCl) is useful to digestion. However, its corrosive effect on the esophagus during reflux can temporarily be neutralized by ingestion of a base such as aluminum hydroxide to produce the neutral molecules water and the salt aluminum chloride. Human biochemistry that involves enzymes usually performs optimally around a biologically neutral pH of 7.4. (Wikipedia). Water, also known as purified water or dihydrogen oxide, is a member of the class of compounds known as homogeneous other non-metal compounds. Homogeneous other non-metal compounds are inorganic non-metallic compounds in which the largest atom belongs to the class of other nonmetals. Water can be found in a number of food items such as caraway, oxheart cabbage, alaska wild rhubarb, and japanese walnut, which makes water a potential biomarker for the consumption of these food products. Water can be found primarily in most biofluids, including ascites Fluid, blood, cerebrospinal fluid (CSF), and lymph, as well as throughout all human tissues. Water exists in all living species, ranging from bacteria to humans. In humans, water is involved in several metabolic pathways, some of which include cardiolipin biosynthesis CL(20:4(5Z,8Z,11Z,14Z)/18:0/20:4(5Z,8Z,11Z,14Z)/18:2(9Z,12Z)), cardiolipin biosynthesis cl(i-13:0/i-15:0/i-20:0/i-24:0), cardiolipin biosynthesis CL(18:0/18:0/20:4(5Z,8Z,11Z,14Z)/22:5(7Z,10Z,13Z,16Z,19Z)), and cardiolipin biosynthesis cl(a-13:0/i-18:0/i-13:0/i-19:0). Water is also involved in several metabolic disorders, some of which include de novo triacylglycerol biosynthesis tg(i-21:0/i-13:0/21:0), de novo triacylglycerol biosynthesis tg(22:0/20:0/i-20:0), de novo triacylglycerol biosynthesis tg(a-21:0/i-20:0/i-14:0), and de novo triacylglycerol biosynthesis tg(i-21:0/a-17:0/i-12:0). Water is a drug which is used for diluting or dissolving drugs for intravenous, intramuscular or subcutaneous injection, according to instructions of the manufacturer of the drug to be administered [fda label]. Water plays an important role in the world economy. Approximately 70\\% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of long-distance trade of commodities (such as oil and natural gas) and manufactured products is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of chemical substances; as such it is widely used in industrial processes, and in cooking and washing. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, and diving .

   

Oxygen

Molecular oxygen

O2 (31.98983)


Oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earths crust. Diatomic oxygen gas constitutes 20.9\\% of the volume of air. All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen in the form of O2 is produced from water by cyanobacteria, algae and plants during photosynthesis and is used in cellular respiration for all living organisms. Green algae and cyanobacteria in marine environments provide about 70\\% of the free oxygen produced on earth and the rest is produced by terrestrial plants. Oxygen is used in mitochondria to help generate adenosine triphosphate (ATP) during oxidative phosphorylation. For animals, a constant supply of oxygen is indispensable for cardiac viability and function. To meet this demand, an adult human, at rest, inhales 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. At a resting pulse rate, the heart consumes approximately 8-15 ml O2/min/100 g tissue. This is significantly more than that consumed by the brain (approximately 3 ml O2/min/100 g tissue) and can increase to more than 70 ml O2/min/100 g myocardial tissue during vigorous exercise. As a general rule, mammalian heart muscle cannot produce enough energy under anaerobic conditions to maintain essential cellular processes; thus, a constant supply of oxygen is indispensable to sustain cardiac function and viability. However, the role of oxygen and oxygen-associated processes in living systems is complex, and they and can be either beneficial or contribute to cardiac dysfunction and death (through reactive oxygen species). Reactive oxygen species (ROS) are a family of oxygen-derived free radicals that are produced in mammalian cells under normal and pathologic conditions. Many ROS, such as the superoxide anion (O2-)and hydrogen peroxide (H2O2), act within blood vessels, altering mechanisms mediating mechanical signal transduction and autoregulation of cerebral blood flow. Reactive oxygen species are believed to be involved in cellular signaling in blood vessels in both normal and pathologic states. The major pathway for the production of ROS is by way of the one-electron reduction of molecular oxygen to form an oxygen radical, the superoxide anion (O2-). Within the vasculature there are several enzymatic sources of O2-, including xanthine oxidase, the mitochondrial electron transport chain, and nitric oxide (NO) synthases. Studies in recent years, however, suggest that the major contributor to O2- levels in vascular cells is the membrane-bound enzyme NADPH-oxidase. Produced O2- can react with other radicals, such as NO, or spontaneously dismutate to produce hydrogen peroxide (H2O2). In cells, the latter reaction is an important pathway for normal O2- breakdown and is usually catalyzed by the enzyme superoxide dismutase (SOD). Once formed, H2O2 can undergo various reactions, both enzymatic and nonenzymatic. The antioxidant enzymes catalase and glutathione peroxidase act to limit ROS accumulation within cells by breaking down H2O2 to H2O. Metabolism of H2O2 can also produce other, more damaging ROS. For example, the endogenous enzyme myeloperoxidase uses H2O2 as a substrate to form the highly reactive compound hypochlorous acid. Alternatively, H2O2 can undergo Fenton or Haber-Weiss chemistry, reacting with Fe2+/Fe3+ ions to form toxic hydroxyl radicals (-.OH). (PMID: 17027622, 15765131) [HMDB]. Oxygen is found in many foods, some of which are soy bean, watermelon, sweet basil, and spinach. Oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earths crust. Diatomic oxygen gas constitutes 20.9\\% of the volume of air. All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen in the form of O2 is produced from water by cyanobacteria, algae and plants during photosynthesis and is used in cellular respiration for all living organisms. Green algae and cyanobacteria in marine environments provide about 70\\% of the free oxygen produced on earth and the rest is produced by terrestrial plants. Oxygen is used in mitochondria to help generate adenosine triphosphate (ATP) during oxidative phosphorylation. For animals, a constant supply of oxygen is indispensable for cardiac viability and function. To meet this demand, an adult human, at rest, inhales 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. At a resting pulse rate, the heart consumes approximately 8-15 ml O2/min/100 g tissue. This is significantly more than that consumed by the brain (approximately 3 ml O2/min/100 g tissue) and can increase to more than 70 ml O2/min/100 g myocardial tissue during vigorous exercise. As a general rule, mammalian heart muscle cannot produce enough energy under anaerobic conditions to maintain essential cellular processes; thus, a constant supply of oxygen is indispensable to sustain cardiac function and viability. However, the role of oxygen and oxygen-associated processes in living systems is complex, and they and can be either beneficial or contribute to cardiac dysfunction and death (through reactive oxygen species). Reactive oxygen species (ROS) are a family of oxygen-derived free radicals that are produced in mammalian cells under normal and pathologic conditions. Many ROS, such as the superoxide anion (O2-)and hydrogen peroxide (H2O2), act within blood vessels, altering mechanisms mediating mechanical signal transduction and autoregulation of cerebral blood flow. Reactive oxygen species are believed to be involved in cellular signaling in blood vessels in both normal and pathologic states. The major pathway for the production of ROS is by way of the one-electron reduction of molecular oxygen to form an oxygen radical, the superoxide anion (O2-). Within the vasculature there are several enzymatic sources of O2-, including xanthine oxidase, the mitochondrial electron transport chain, and nitric oxide (NO) synthases. Studies in recent years, however, suggest that the major contributor to O2- levels in vascular cells is the membrane-bound enzyme NADPH-oxidase. Produced O2- can react with other radicals, such as NO, or spontaneously dismutate to produce hydrogen peroxide (H2O2). In cells, the latter reaction is an important pathway for normal O2- breakdown and is usually catalyzed by the enzyme superoxide dismutase (SOD). Once formed, H2O2 can undergo various reactions, both enzymatic and nonenzymatic. The antioxidant enzymes catalase and glutathione peroxidase act to limit ROS accumulation within cells by breaking down H2O2 to H2O. Metabolism of H2O2 can also produce other, more damaging ROS. For example, the endogenous enzyme myeloperoxidase uses H2O2 as a substrate to form the highly reactive compound hypochlorous acid. Alternatively, H2O2 can undergo Fenton or Haber-Weiss chemistry, reacting with Fe2+/Fe3+ ions to form toxic hydroxyl radicals (-.OH). (PMID: 17027622, 15765131). V - Various > V03 - All other therapeutic products > V03A - All other therapeutic products > V03AN - Medical gases

   

Retinyl palmitate

(2E,4E,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethyl-cyclohex-1-enyl)-nona-2,4,6,8,tetraenyl hexadecanoic acid ester

C36H60O2 (524.459306)


Retinyl palmitate, also known as vitamin a palmitate or aquasol a, is a member of the class of compounds known as wax monoesters. Wax monoesters are waxes bearing an ester group at exactly one position. Thus, retinyl palmitate is considered to be an isoprenoid lipid molecule. Retinyl palmitate is practically insoluble (in water) and an extremely weak basic (essentially neutral) compound (based on its pKa). Retinyl palmitate can be found in a number of food items such as rocket salad (sspecies), black elderberry, common grape, and vaccinium (blueberry, cranberry, huckleberry), which makes retinyl palmitate a potential biomarker for the consumption of these food products. Retinyl palmitate can be found primarily in blood, as well as throughout most human tissues. In humans, retinyl palmitate is involved in the retinol metabolism. Retinyl palmitate is also involved in vitamin A deficiency, which is a metabolic disorder. An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen . Retinyl palmitate, or vitamin A palmitate, is a common vitamin supplement, with formula C36H60O2. It is available in both oral and injectable forms for treatment of vitamin A deficiency, under the brand names Aquasol and Palmitate. Retinyl palmitate is an alternate for retinyl acetate in vitamin A supplements, and is available in oily or dry forms. It is a pre-formed version of vitamin A, and can thus be realistically over-dosed, unlike beta-carotene. C274 - Antineoplastic Agent > C2122 - Cell Differentiating Agent > C1934 - Differentiation Inducer C274 - Antineoplastic Agent > C163758 - Targeted Therapy Agent > C804 - Retinoic Acid Agent C308 - Immunotherapeutic Agent > C129820 - Antineoplastic Immunomodulating Agent D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D020011 - Protective Agents > D016588 - Anticarcinogenic Agents D000970 - Antineoplastic Agents Retinyl palmitate is an ester of Retinol and is the major form of vitamin A found in the epidermis. Retinyl palmitate has been widely used in pharmaceutical and cosmetic formulations.

   

4-Hydroxyretinoic acid

(2E,4E,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethyl-3-hydroxy-1-cyclohexen-1-yl)-2,4,6,8-nonatetraenoic acid

C20H28O3 (316.2038338)


4-Hydroxyretinoic acid is an NADPH-dependent hydroxylation metabolite of retinoic acid in the microsomes, via the cytochrome P-450 system. Retinoic acid is an activated metabolite of retinol that supports the systemic functions of vitamin A in vivo. (PMID: 1538719, 1932598, 2851384) [HMDB] 4-Hydroxyretinoic acid is an NADPH-dependent hydroxylation metabolite of retinoic acid in the microsomes, via the cytochrome P-450 system. Retinoic acid is an activated metabolite of retinol that supports the systemic functions of vitamin A in vivo. (PMID: 1538719, 1932598, 2851384). D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

4-Ketoretinoic acid

all-trans-4-Oxoretinoic acid

C20H26O3 (314.1881846)


D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids all-trans-4-Oxoretinoic acid, an active metabolite of vitamin A, induces gene transcription via binding to nuclear retinoic acid receptors (RARs).

   

all-trans-5,6-Epoxyretinoic acid

(2E,4E,6E,8E)-3,7-dimethyl-9-{2,2,6-trimethyl-7-oxabicyclo[4.1.0]heptan-1-yl}nona-2,4,6,8-tetraenoic acid

C20H28O3 (316.2038338)


all-trans-5,6-Epoxyretinoic acid, also known as 5,6-epoxy-atRA, is classified as a member of the retinoids. Retinoids are oxygenated derivatives of 3,7-dimethyl-1-(2,6,6-trimethylcyclohex-1-enyl)nona-1,3,5,7-tetraene and derivatives thereof. all-trans-5,6-Epoxyretinoic acid is considered to be a practically insoluble (in water) and a weak acidic compound. all-trans-5,6-Epoxyretinoic acid is an isoprenoid lipid molecule. all-trans-5,6-Epoxyretinoic acid can be found primarily in human kidney and liver tissues; and in blood and urine. Within a cell, all-trans-5,6-epoxyretinoic acid is primarily located in the cytoplasm, in the extracellular space, or near the membrane. A human metabolite taken as a putative food compound of mammalian origin [HMDB] D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

11-cis-Retinaldehyde

(2E,4Z,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenal

C20H28O (284.2140038)


11-cis-retinal is a retinal having 2E,4Z,6E,8E-double bond geometry. It has a role as a chromophore, a human metabolite and a mouse metabolite. It is a diterpene derived from the carotenoid vitamin A which functions as the active component of the visual cycle. It is the prosthetic group of rhodopsin. When stimulated by visible light, rhodopsin transforms this cis-isomer of retinal to the trans-isomer (11-trans-retinal). This transformation straightens-out the bend of the retinal molecule and causes a change in the shape of rhodopsin triggering the visual process. A series of energy-requiring enzyme-catalyzed reactions convert the 11-trans-retinal back to the cis-isomer. 11-cis-retinal functions in the retina in the transduction of light into the neural signals necessary for vision. 11-cis-retinal, while attached to opsin in rhodopsin is isomerized to all-trans-retinal by light. This is the event that triggers the nerve impulse to the brain which allows for the perception of light. All-trans-retinal is then released from opsin and reduced to all-trans-retinol. All-trans-retinol is isomerized to 11-cis-retinol in the dark, and then oxidized to 11-cis-retinal. 11-cis-retinal recombines with opsin to re-form rhodopsin. Night blindness or defective vision at low illumination results from a failure to resynthesize 11-cis retinal rapidly. Vitamin A (all-trans retinol) is converted in the retina to the 11-cis-isomer of retinaldehyde or 11-cis-retinal. 11-cis-retinal functions in the retina in the transduction of light into the neural signals necessary for vision. 11-cis-retinal, while attached to opsin in rhodopsin is isomerized to all-trans-retinal by light. This is the event that triggers the nerve impulse to the brain which allows for the perception of light. All-trans-retinal is then released from opsin and reduced to all-trans-retinol. All-trans-retinol is isomerized to 11-cis-retinol in the dark, and then oxidized to 11-cis-retinal. 11-cis-retinal recombines with opsin to re-form rhodopsin. Night blindness or defective vision at low illumination results from a failure to resynthesize 11-cis retinal rapidly. D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

9-cis-Retinoic acid

(2E,4E,6Z,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenoic acid

C20H28O2 (300.2089188)


9-cis-Retinoic acid is an active retinoid that regulates expression of retinoid responsive genes, serving as a ligand for two classes of ligand-dependent transcription factors: the retinoic acid receptors and retinoid X receptors. Retinoids (vitamin A and its analogs) are essential dietary substances that are needed by mammals for reproduction, normal embryogenesis, growth, vision, and maintaining normal cellular differentiation and the integrity of the immune system. Within cells, retinoids regulate gene transcription acting through ligand-dependent transcription factors, the retinoic acid receptors (RARs), and the retinoid X receptors (RXRs). all-trans-Retinoic acid binds only to RARs with high affinity, whereas its 9-cis isomer binds with high affinity to both RARs and RXRs. The actions of all-trans- and 9-cis-retinoic acid in regulating cellular responses are distinct and not interchangeable (PMID: 9115228). Isolated from pancreas of pig and cow. Digestive enzyme. It is used in replacement therapy. It is used to prepare protein hydrolysates for pre- and post-operative diets D - Dermatologicals > D11 - Other dermatological preparations > D11A - Other dermatological preparations > D11AH - Agents for dermatitis, excluding corticosteroids L - Antineoplastic and immunomodulating agents > L01 - Antineoplastic agents > L01X - Other antineoplastic agents > L01XF - Retinoids for cancer treatment C274 - Antineoplastic Agent > C2122 - Cell Differentiating Agent > C1934 - Differentiation Inducer C274 - Antineoplastic Agent > C163758 - Targeted Therapy Agent > C804 - Retinoic Acid Agent C308 - Immunotherapeutic Agent > C129820 - Antineoplastic Immunomodulating Agent D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D000970 - Antineoplastic Agents D003879 - Dermatologic Agents Same as: D02815

   

11-cis-Retinol

3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol, (all-e)-isomer

C20H30O (286.229653)


Cis-11-retinol is produce from vitamin A cycle driven by interphotoreceptor retinoid binding protein(IRBP). cis-11-retinol is released from retinal pigment epithelium(RPE) membranes. (PMID: 10655150). Retinoid metabolism of RPE cells freshly isolated by trypsinization showed no 11- cis -retinal and little 11- cis -retinol formation. Nondamaged cells cultured on thermally responsive surfaces detached in sheets upon temperature change. They showed metabolism similar to that of cells freshly isolated by nonenzymatic means. After trypsinization, confluent cultures dissociated into individual cells, but these cells showed poor retinoid metabolism, including no detectable retinyl esters or 11- cis -retinoid isomers. (PMID: 10375454). Cis-11-retinol is produce from vitamin A cycle driven by interphotoreceptor retinoid binding protein(IRBP). cis-11-retinol is released from retinal pigment epithelium(RPE) membranes. (PMID: 10655150) D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D018977 - Micronutrients > D014815 - Vitamins

   

9-cis-Retinol

(2E,4E,6Z,8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-ol

C20H30O (286.229653)


9-cis-retinol is a retinoid. Retinoids (vitamin A and its analogs) are essential dietary substances that are needed by mammals for reproduction, normal embryogenesis, growth, vision, and maintaining normal cellular differentiation and the integrity of the immune system. Within cells, retinoids regulate gene transcription acting through ligand-dependent transcription factors, the retinoic acid receptors (RARs), and the retinoid X receptors (RXRs). All-trans-retinoic acid binds only to RARs with high affinity, whereas its 9-cis isomer binds with high affinity to both RARs and RXRs. The actions of all-trans- and 9-cis-retinoic acid in regulating cellular responses are distinct and not interchangeable. (PMID: 9115228). Constituent of cod liver oil

   

9-cis-Retinal

(2E,4E,6Z,8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenal

C20H28O (284.2140038)


In vivo, 9-cis-retinal is formed through oxidation of 9-cis-retinol by cis-retinol dehydrogenase (cRDH). (PMID:15572038). The generation of retinoic acid from retinol is a two-step reaction, with the rate-limiting step being the oxidation of retinol into the intermediate retinaldehyde. Two classes of. unrelated enzymes have been implicated in the oxidation of retinol, the classical cytosolic medium chain alcohol dehydrogenases and recently identified microsomal members of the short chain alcohol dehydrogenase reductase (SDR) superfamily. Further oxidation of the retinaldehyde to the retinoic acid is believed to be catalyzed by several cytosolic aldehyde dehydrogenases. Retinoids are micronutrients required to maintain and promote health of vertebrates. They act physiologically by participating in the visual cycle, in regulating cell differentiation, in embryonic development (PMID:10893430), in maintaining normal reproduction, and in the immune response (PMID:8882153). In non-ocular tissues, the effects of retinoids within the body are mediated through retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which act to regulate gene expression as ligand-dependent transcription factors. The naturally occurring ligands for these nuclear receptors are thought to be all-trans-retinoic acid for RARs and 9-cis-retinoic acid for RXRs (PMID:10322133). While many details of the molecular actions of the RARs and RXRs in regulating gene transcription are understood (PMID:10418975), tissue-specific synthetic pathway(s) of their ligands has not been adequately defined. Nevertheless, the therapeutic efficacy of retinoids, including 9-cis-retinoic acid, is well established in both tissue culture and animal models of breast cancer (PMID:8825126, PMID:12743994). In vivo, 9-cis-retinal is formed through oxidation of 9-cis-retinol by cis-retinol dehydrogenase (cRDH). (PMID: 15572038). The generation of retinoic acid from retinol is a two-step reaction, with the rate-limiting step being the oxidation of retinol into the intermediate retinaldehyde. Two classes of D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

all-trans-18-Hydroxyretinoic acid

(2E,4E,6E,8E)-9-[2-(hydroxymethyl)-6,6-dimethylcyclohex-1-en-1-yl]-3,7-dimethylnona-2,4,6,8-tetraenoic acid

C20H28O3 (316.2038338)


A retinoid that consists of all-trans-retinoic acid bearing an hydroxy substituent at position 18.

   

Retinyl ester

(2E,4E,6E,8E)-3,7-dimethyl-9-(2,2,6-trimethylcyclohexyl)nona-2,4,6,8-tetraenoic acid

C20H30O2 (302.224568)


Retinyl ester is a substrate for Lecithin retinol acyltransferase and Retinal pigment epithelium-specific 65 kDa protein. [HMDB] Retinyl ester is a substrate for Lecithin retinol acyltransferase and Retinal pigment epithelium-specific 65 kDa protein. D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids

   

DG(16:1(9Z)/22:0/0:0)

(2S)-1-[(9Z)-hexadec-9-enoyloxy]-3-hydroxypropan-2-yl docosanoate

C41H78O5 (650.5848937999999)


DG(16:1(9Z)/22:0/0:0) is a diglyceride, or a diacylglycerol (DAG). It is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Diacylglycerols can have many different combinations of fatty acids attached at both the C-1 and C-2 positions. DG(16:1(9Z)/22:0/0:0), in particular, consists of one chain of palmitoleic acid at the C-1 position and one chain of behenic acid at the C-2 position. The palmitoleic acid moiety is derived from animal fats and vegetable oils, while the behenic acid moiety is derived from groundnut oil. Mono- and diacylglycerols are common food additives used to blend together certain ingredients, such as oil and water, which would not otherwise blend well. Dacylglycerols are often found in bakery products, beverages, ice cream, chewing gum, shortening, whipped toppings, margarine, and confections. Synthesis of diacylglycerol begins with glycerol-3-phosphate, which is derived primarily from dihydroxyacetone phosphate, a product of glycolysis (usually in the cytoplasm of liver or adipose tissue cells). Glycerol-3-phosphate is first acylated with acyl-coenzyme A (acyl-CoA) to form lysophosphatidic acid, which is then acylated with another molecule of acyl-CoA to yield phosphatidic acid. Phosphatidic acid is then de-phosphorylated to form diacylglycerol.Diacylglycerols are precursors to triacylglycerols (triglyceride), which are formed by the addition of a third fatty acid to the diacylglycerol under the catalysis of diglyceride acyltransferase. Since diacylglycerols are synthesized via phosphatidic acid, they will usually contain a saturated fatty acid at the C-1 position on the glycerol moiety and an unsaturated fatty acid at the C-2 position.

   

PC(24:1(15Z)/15:0)

trimethyl(2-{[(2R)-2-(pentadecanoyloxy)-3-[(15Z)-tetracos-15-enoyloxy]propyl phosphonato]oxy}ethyl)azanium

C47H92NO8P (829.6560202)


PC(24:1(15Z)/15:0) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(24:1(15Z)/15:0), in particular, consists of one chain of nervonic acid at the C-1 position and one chain of pentadecanoic acid at the C-2 position. The nervonic acid moiety is derived from fish oils, while the pentadecanoic acid moiety is derived from dairy products and milk fat. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.

   

TG(16:1(9Z)/22:0/16:1(9Z))

1-(9Z-Hexadecenoyl)-2-docosanoyl-3-(9Z-hexadecenoyl)-glycerol

C57H106O6 (886.7988975999999)


TG(16:1(9Z)/22:0/16:1(9Z)) is a dipalmitoleic acid triglyceride. Triglycerides (TGs or TAGs) are also known as triacylglycerols or triacylglycerides, meaning that they are glycerides in which the glycerol is esterified with three fatty acid groups (i.e. fatty acid trimesters of glycerol). TGs may be divided into three general types with respect to their acyl substituents. They are simple or monoacid if they contain only one type of fatty acid, diacid if they contain two types of fatty acids and triacid if three different acyl groups. Chain lengths of the fatty acids in naturally occurring triglycerides can be of varying lengths and saturations but 16, 18 and 20 carbons are the most common. TG(16:1(9Z)/22:0/16:1(9Z)), in particular, consists of one chain of palmitoleic acid at the C-1 position, one chain of behenic acid at the C-2 position and one chain of palmitoleic acid at the C-3 position. TGs are the main constituent of vegetable oil and animal fats. TGs are major components of very low density lipoprotein (VLDL) and chylomicrons, play an important role in metabolism as energy sources and transporters of dietary fat. They contain more than twice the energy (9 kcal/g) of carbohydrates and proteins. In the intestine, triglycerides are split into glycerol and fatty acids (this process is called lipolysis) with the help of lipases and bile secretions, which can then move into blood vessels. The triglycerides are rebuilt in the blood from their fragments and become constituents of lipoproteins, which deliver the fatty acids to and from fat cells among other functions. Various tissues can release the free fatty acids and take them up as a source of energy. Fat cells can synthesize and store triglycerides. When the body requires fatty acids as an energy source, the hormone glucagon signals the breakdown of the triglycerides by hormone-sensitive lipase to release free fatty acids. As the brain cannot utilize fatty acids as an energy source, the glycerol component of triglycerides can be converted into glucose for brain fuel when it is broken down. (www.cyberlipid.org, www.wikipedia.org)
TAGs can serve as fatty acid stores in all cells, but primarily in adipocytes of adipose tissue. The major building block for the synthesis of triacylglycerides, in non-adipose tissue, is glycerol. Adipocytes lack glycerol kinase and so must use another route to TAG synthesis. Specifically, dihydroxyacetone phosphate (DHAP), which is produced during glycolysis, is the precursor for TAG synthesis in adipose tissue. DHAP can also serve as a TAG precursor in non-adipose tissues, but does so to a much lesser extent than glycerol. The use of DHAP for the TAG backbone depends on whether the synthesis of the TAGs occurs in the mitochondria and ER or the ER and the peroxisomes. The ER/mitochondria pathway requires the action of glycerol-3-phosphate dehydrogenase to convert DHAP to glycerol-3-phosphate. Glycerol-3-phosphate acyltransferase then esterifies a fatty acid to glycerol-3-phosphate thereby generating lysophosphatidic acid. The ER/peroxisome reaction pathway uses the peroxisomal enzyme DHAP acyltransferase to acylate DHAP to acyl-DHAP which is then reduced by acyl-DHAP reductase. The fatty acids that are incorporated into TAGs are activated to acyl-CoAs through the action of acyl-CoA synthetases. Two molecules of acyl-CoA are esterified to glycerol-3-phosphate to yield 1,2-diacylglycerol phosphate (also known as phosphatidic acid). The phosphate is then removed by phosphatidic acid phosphatase (PAP1), to generate 1,2-diacylglycerol. This diacylglycerol serves as the substrate for addition of the third fatty acid to make TAG. Intestinal monoacylglycerols, derived from dietary fats, can also serve as substrates for the synthesis of 1,2-diacylglycerols.

   

(2S)-2,3-dihydroxypropyl 2-(trimethylazaniumyl)ethyl phosphate

(2S)-2,3-dihydroxypropyl 2-(trimethylazaniumyl)ethyl phosphate

C8H20NO6P (257.102819)


   

ent-NADPH

Dihydrocodehydrogenase II

C21H30N7O17P3 (745.0911)


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