Reaction Process: Reactome:R-ATH-1614558
Degradation of cysteine and homocysteine related metabolites
find 22 related metabolites which is associated with chemical reaction(pathway) Degradation of cysteine and homocysteine
H2O + HCYS ⟶ 2OBUTA + H2S + ammonia
Homocysteine
A high level of blood serum homocysteine is a powerful risk factor for cardiovascular disease. Unfortunately, one study which attempted to decrease the risk by lowering homocysteine was not fruitful. This study was conducted on nearly 5000 Norwegian heart attack survivors who already had severe, late-stage heart disease. No study has yet been conducted in a preventive capacity on subjects who are in a relatively good state of health.; Elevated levels of homocysteine have been linked to increased fractures in elderly persons. The high level of homocysteine will auto-oxidize and react with reactive oxygen intermediates and damage endothelial cells and has a higher risk to form a thrombus. Homocysteine does not affect bone density. Instead, it appears that homocysteine affects collagen by interfering with the cross-linking between the collagen fibers and the tissues they reinforce. Whereas the HOPE-2 trial showed a reduction in stroke incidence, in those with stroke there is a high rate of hip fractures in the affected side. A trial with 2 homocysteine-lowering vitamins (folate and B12) in people with prior stroke, there was an 80\\\\\\% reduction in fractures, mainly hip, after 2 years. Interestingly, also here, bone density (and the number of falls) were identical in the vitamin and the placebo groups.; Homocysteine is a sulfur-containing amino acid that arises during methionine metabolism. Although its concentration in plasma is only about 10 micromolar (uM), even moderate hyperhomocysteinemia is associated with increased incidence of cardiovascular disease and Alzheimers disease. Elevations in plasma homocysteine are commonly found as a result of vitamin deficiencies, polymorphisms of enzymes of methionine metabolism, and renal disease. Pyridoxal, folic acid, riboflavin, and Vitamin B(12) are all required for methionine metabolism, and deficiency of each of these vitamins result in elevated plasma homocysteine. A polymorphism of methylenetetrahydrofolate reductase (C677T), which is quite common in most populations with a homozygosity rate of 10-15 \\\\\\%, is associated with moderate hyperhomocysteinemia, especially in the context of marginal folate intake. Plasma homocysteine is inversely related to plasma creatinine in patients with renal disease. This is due to an impairment in homocysteine removal in renal disease. The role of these factors, and of modifiable lifestyle factors, in affecting methionine metabolism and in determining plasma homocysteine levels is discussed. Homocysteine is an independent cardiovascular disease (CVD) risk factor modifiable by nutrition and possibly exercise. Homocysteine was first identified as an important biological compound in 1932 and linked with human disease in 1962 when elevated urinary homocysteine levels were found in children with mental retardation. This condition, called homocysteinuria, was later associated with premature occlusive CVD, even in children. These observations led to research investigating the relationship of elevated homocysteine levels and CVD in a wide variety of populations including middle age and elderly men and women with and without traditional risk factors for CVD. (PMID 17136938, 15630149); Homocysteine is an amino acid with the formula HSCH2CH2CH(NH2)CO2H. It is a homologue of the amino acid cysteine, differing by an additional methylene (-CH2-) group. It is biosynthesized from methionine by the removal of its terminal C? methyl group. Homocysteine can be recycled into methionine or converted into cysteine with the aid of B-vitamins.; Studies reported in 2006 have shown that giving vitamins [folic acid, B6 and B12] to reduce homocysteine levels may not quickly offer benefit, however a significant 25\\\\\\% reduction in stroke was found in the HOPE-2 study even in patients mostly with existing serious arterial decline although the overall death rate was not significantly changed by the intervention in the trial. Clearly, reducing homocysteine does not quickly repair existing... Homocysteine (CAS: 454-29-5) is a sulfur-containing amino acid that arises during methionine metabolism. Although its concentration in plasma is only about 10 micromolar (uM), even moderate hyperhomocysteinemia is associated with an increased incidence of cardiovascular disease and Alzheimers disease. Elevations in plasma homocysteine are commonly found as a result of vitamin deficiencies, polymorphisms of enzymes of methionine metabolism, and renal disease. It has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Pyridoxal, folic acid, riboflavin, and vitamin B(12) are all required for methionine metabolism, and deficiency of each of these vitamins result in elevated plasma homocysteine. A polymorphism of methylenetetrahydrofolate reductase (C677T), which is quite common in most populations with a homozygosity rate of 10-15 \\\\\\%, is associated with moderate hyperhomocysteinemia, especially in the context of marginal folate intake. Plasma homocysteine is inversely related to plasma creatinine in patients with renal disease. This is due to an impairment in homocysteine removal in renal disease. The role of these factors, and of modifiable lifestyle factors, in affecting methionine metabolism and in determining plasma homocysteine levels is discussed. Homocysteine is an independent cardiovascular disease (CVD) risk factor modifiable by nutrition and possibly exercise. Homocysteine was first identified as an important biological compound in 1932 and linked with human disease in 1962 when elevated urinary homocysteine levels were found in children with mental retardation. This condition, called homocystinuria, was later associated with premature occlusive CVD, even in children. These observations led to research investigating the relationship of elevated homocysteine levels and CVD in a wide variety of populations including middle age and elderly men and women with and without traditional risk factors for CVD (PMID: 17136938 , 15630149). Moreover, homocysteine is found to be associated with cystathionine beta-synthase deficiency, cystathioninuria, methylenetetrahydrofolate reductase deficiency, and sulfite oxidase deficiency, which are inborn errors of metabolism. [Spectral] L-Homocysteine (exact mass = 135.0354) and L-Valine (exact mass = 117.07898) 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. Homocysteine is biosynthesized naturally via a multi-step process.[9] First, methionine receives an adenosine group from ATP, a reaction catalyzed by S-adenosyl-methionine synthetase, to give S-adenosyl methionine (SAM-e). SAM-e then transfers the methyl group to an acceptor molecule, (e.g., norepinephrine as an acceptor during epinephrine synthesis, DNA methyltransferase as an intermediate acceptor in the process of DNA methylation). The adenosine is then hydrolyzed to yield L-homocysteine. L-Homocysteine has two primary fates: conversion via tetrahydrofolate (THF) back into L-methionine or conversion to L-cysteine.[10] Biosynthesis of cysteine Mammals biosynthesize the amino acid cysteine via homocysteine. Cystathionine β-synthase catalyses the condensation of homocysteine and serine to give cystathionine. This reaction uses pyridoxine (vitamin B6) as a cofactor. Cystathionine γ-lyase then converts this double amino acid to cysteine, ammonia, and α-ketobutyrate. Bacteria and plants rely on a different pathway to produce cysteine, relying on O-acetylserine.[11] Methionine salvage Homocysteine can be recycled into methionine. This process uses N5-methyl tetrahydrofolate as the methyl donor and cobalamin (vitamin B12)-related enzymes. More detail on these enzymes can be found in the article for methionine synthase. Other reactions of biochemical significance Homocysteine can cyclize to give homocysteine thiolactone, a five-membered heterocycle. Because of this "self-looping" reaction, homocysteine-containing peptides tend to cleave themselves by reactions generating oxidative stress.[12] Homocysteine also acts as an allosteric antagonist at Dopamine D2 receptors.[13] It has been proposed that both homocysteine and its thiolactone may have played a significant role in the appearance of life on the early Earth.[14] L-Homocysteine. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=454-28-4 (retrieved 2024-06-29) (CAS RN: 6027-13-0). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0). DL-Homocysteine is a weak neurotoxin, and can affect the production of kynurenic acid in the brain. DL-Homocysteine is a weak neurotoxin, and can affect the production of kynurenic acid in the brain. L-Homocysteine, a homocysteine metabolite, is a homocysteine that has L configuration. L-Homocysteine induces upregulation of cathepsin V that mediates vascular endothelial inflammation in hyperhomocysteinaemia[1][2].
Hypotaurine
Hypotaurine belongs to the class of organic compounds known as sulfinic acids. Sulfinic acids are compounds containing a sulfinic acid functional group, with the general structure RS(=O)OH (R = organyl, not H). Hypotaurine exists in all living species, ranging from bacteria to humans. Within humans, hypotaurine participates in a number of enzymatic reactions. In particular, hypotaurine can be biosynthesized from cysteamine; which is catalyzed by the enzyme 2-aminoethanethiol dioxygenase. In addition, hypotaurine can be biosynthesized from 3-sulfinoalanine through its interaction with the enzyme cysteine sulfinic acid decarboxylase. In humans, hypotaurine is involved in taurine and hypotaurine metabolism. [Spectral] Hypotaurine (exact mass = 109.01975) and Cytosine (exact mass = 111.04326) 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. Hypotaurine is a product of enzyme cysteamine dioxygenase [EC 1.13.11.19] in taurine and hypotaurine metabolism pathway (KEGG). It may function as an antioxidant and a protective agent under physiological conditions (PMID 14992269). [HMDB] Hypotaurine (2-aminoethanesulfinic acid), an intermediate in taurine biosynthesis from cysteine in astrocytes, is an endogenous inhibitory amino acid of the glycine receptor. Antioxidant[1].
Cysteamine
Cysteamine is a product of the constitutive degradation of coenzyme A, a process that occurs in all tissues, although some tissues such as brain and heart may have exceptionally high coenzyme A turnover rates. Cysteamine has only one known function, and that is as a precursor for the formation of hypotaurine, which is subsequently oxidized to taurine. The rate of cysteamine production as a result of coenzyme A breakdown is not well understood but it is clear that cysteamine levels are not as dramatically affected by dietary habits as are cysteine levels. Cysteamine is generated from hypotaurine by cysteamine dioxygenase (EC:1.13.11.19), an enzyme that was recently identified in mammals (PMID: 17581819). Cysteamine is the simplest stable aminothiol found in the body. It is used in the treatment of disorders of cystine excretion. Cysteamine cleaves the disulfide bond with cysteine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria. Cyst(e)amine may also serve as an endogenous regulator of immune system activity as well as a potential therapeutic agent for the treatment of Huntington disease. Cysteamine is also used as a radiation-protective agent that oxidizes in air to form cystamine. It can be given intravenously or orally to treat radiation sickness. -- Wikipedia [HMDB] Cysteamine is a product of the constitutive degradation of coenzyme A, a process that occurs in all tissues, although some tissues such as brain and heart may have exceptionally high coenzyme A turnover rates. Cysteamine has only one known function, and that is as a precursor for the formation of hypotaurine, which is subsequently oxidized to taurine. The rate of cysteamine production as a result of coenzyme A breakdown is not well understood but it is clear that cysteamine levels are not as dramatically affected by dietary habits as are cysteine levels. Cysteamine is generated from hypotaurine by cysteamine dioxygenase (EC:1.13.11.19), an enzyme that was recently identified in mammals (PMID:17581819). Cysteamine is the simplest stable aminothiol found in the body. It is used in the treatment of disorders of cystine excretion. Cysteamine cleaves the disulfide bond with cysteine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria. Cyst(e)amine may also serve as an endogenous regulator of immune system activity as well as a potential therapeutic agent for the treatment of Huntington disease. Cysteamine is also used as a radiation-protective agent that oxidizes in air to form cystamine. It can be given intravenously or orally to treat radiation sickness. A - Alimentary tract and metabolism > A16 - Other alimentary tract and metabolism products > A16A - Other alimentary tract and metabolism products > A16AA - Amino acids and derivatives C78276 - Agent Affecting Digestive System or Metabolism > C29701 - Anti-ulcer Agent S - Sensory organs > S01 - Ophthalmologicals D065104 - Cystine Depleting Agents
Alpha-ketobutyrate
3-methyl pyruvic acid, also known as alpha-ketobutyric acid or 2-oxobutyric acid, belongs to short-chain keto acids and derivatives class of compounds. Those are keto acids with an alkyl chain the contains less than 6 carbon atoms. Thus, 3-methyl pyruvic acid is considered to be a fatty acid lipid molecule. 3-methyl pyruvic acid is soluble (in water) and a weakly acidic compound (based on its pKa). 3-methyl pyruvic acid can be found in a number of food items such as pepper (c. baccatum), triticale, european plum, and black walnut, which makes 3-methyl pyruvic acid a potential biomarker for the consumption of these food products. 3-methyl pyruvic acid can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine. 3-methyl pyruvic acid exists in all living species, ranging from bacteria to humans. In humans, 3-methyl pyruvic acid is involved in several metabolic pathways, some of which include methionine metabolism, homocysteine degradation, threonine and 2-oxobutanoate degradation, and propanoate metabolism. 3-methyl pyruvic acid is also involved in several metabolic disorders, some of which include dimethylglycine dehydrogenase deficiency, methylenetetrahydrofolate reductase deficiency (MTHFRD), s-adenosylhomocysteine (SAH) hydrolase deficiency, and hyperglycinemia, non-ketotic. 2-Ketobutyric acid, also known as alpha-ketobutyrate or 2-oxobutyrate, belongs to the class of organic compounds known as short-chain keto acids and derivatives. These are keto acids with an alkyl chain the contains less than 6 carbon atoms. 2-Ketobutyric acid is a substance that is involved in the metabolism of many amino acids (glycine, methionine, valine, leucine, serine, threonine, isoleucine) as well as propanoate metabolism and C-5 branched dibasic acid metabolism. It is also one of the degradation products of threonine. It can be converted into propionyl-CoA (and subsequently methylmalonyl CoA, which can be converted into succinyl CoA, a citric acid cycle intermediate), and thus enter the citric acid cycle. More specifically, 2-ketobutyric acid is a product of the lysis of cystathionine. 2-Oxobutanoic acid is a product in the enzymatic cleavage of cystathionine.
Pyruvate
Pyruvic acid, also known as 2-oxopropanoic acid or alpha-ketopropionic acid, belongs to alpha-keto acids and derivatives class of compounds. Those are organic compounds containing an aldehyde substituted with a keto group on the adjacent carbon. Thus, pyruvic acid is considered to be a fatty acid lipid molecule. Pyruvic acid is soluble (in water) and a moderately acidic compound (based on its pKa). Pyruvic acid can be synthesized from propionic acid. Pyruvic acid is also a parent compound for other transformation products, including but not limited to, 4-hydroxy-3-iodophenylpyruvate, 3-acylpyruvic acid, and methyl pyruvate. Pyruvic acid can be found in a number of food items such as kumquat, groundcherry, coconut, and prunus (cherry, plum), which makes pyruvic acid a potential biomarker for the consumption of these food products. Pyruvic acid can be found primarily in most biofluids, including sweat, blood, urine, and feces, as well as throughout most human tissues. Pyruvic acid exists in all living species, ranging from bacteria to humans. In humans, pyruvic acid is involved in several metabolic pathways, some of which include glycogenosis, type IB, glycolysis, urea cycle, and gluconeogenesis. Pyruvic acid is also involved in several metabolic disorders, some of which include non ketotic hyperglycinemia, pyruvate dehydrogenase complex deficiency, fructose-1,6-diphosphatase deficiency, and 4-hydroxybutyric aciduria/succinic semialdehyde dehydrogenase deficiency. Moreover, pyruvic acid is found to be associated with anoxia, schizophrenia, fumarase deficiency, and meningitis. Pyruvic acid is a non-carcinogenic (not listed by IARC) potentially toxic compound. Pyruvic acid is a drug which is used for nutritional supplementation, also for treating dietary shortage or imbalanc. Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA. It can also be used to construct the amino acid alanine and can be converted into ethanol or lactic acid via fermentation . Those taking large doses of supplemental pyruvate—usually greater than 5 grams daily—have reported gastrointestinal symptoms, including abdominal discomfort and bloating, gas and diarrhea. One child receiving pyruvate intravenously for restrictive cardiomyopathy died (DrugBank). Pyruvate serves as a biological fuel by being converted to acetyl coenzyme A, which enters the tricarboxylic acid or Krebs cycle where it is metabolized to produce ATP aerobically. Energy can also be obtained anaerobically from pyruvate via its conversion to lactate. Pyruvate injections or perfusions increase contractile function of hearts when metabolizing glucose or fatty acids. This inotropic effect is striking in hearts stunned by ischemia/reperfusion. The inotropic effect of pyruvate requires intracoronary infusion. Among possible mechanisms for this effect are increased generation of ATP and an increase in ATP phosphorylation potential. Another is activation of pyruvate dehydrogenase, promoting its own oxidation by inhibiting pyruvate dehydrogenase kinase. Pyruvate dehydrogenase is inactivated in ischemia myocardium. Yet another is reduction of cytosolic inorganic phosphate concentration. Pyruvate, as an antioxidant, is known to scavenge such reactive oxygen species as hydrogen peroxide and lipid peroxides. Indirectly, supraphysiological levels of pyruvate may increase cellular reduced glutathione (T3DB). Pyruvic acid or pyruvate is a simple alpha-keto acid. It is a three-carbon molecule containing a carboxylic acid group and a ketone functional group. Pyruvate is the simplest alpha-keto acid and according to official nomenclature by IUPAC, it is called alpha-keto propanoic acid. Like other keto acids, pyruvic acid can tautomerize from its ketone form to its enol form, containing a double bond and an alcohol. Pyruvate is found in all living organisms ranging from bacteria to plants to humans. It is intermediate compound in the metabolism of carbohydrates, proteins, and fats. Pyruvate is a key intermediate in several metabolic pathways throughout the cell. In particular, pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA. Pyruvic acid supplies energy to cells through the citric acid cycle (TCA or Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking (lactic acid). In glycolysis, phosphoenolpyruvate (PEP) is converted to pyruvate by pyruvate kinase. This reaction is strongly exergonic and irreversible. In gluconeogenesis, it takes two enzymes, pyruvate carboxylase and PEP carboxykinase, to catalyze the reverse transformation of pyruvate to PEP. Pyruvic acid is also a metabolite of Corynebacterium (PMID: 27872963). Pyruvic acid. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=127-17-3 (retrieved 2024-07-01) (CAS RN: 127-17-3). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0). Pyruvic acid is an intermediate metabolite in the metabolism of carbohydrates, proteins, and fats. Pyruvic acid is an intermediate metabolite in the metabolism of carbohydrates, proteins, and fats.
Water
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
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
ammonia
An azane that consists of a single nitrogen atom covelently bonded to three hydrogen atoms. Ammonia, also known as nh3 or ammonia solution, 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. Ammonia can be found in a number of food items such as rose hip, yardlong bean, cereals and cereal products, and ceylon cinnamon, which makes ammonia a potential biomarker for the consumption of these food products. Ammonia can be found primarily in blood, cellular cytoplasm, cerebrospinal fluid (CSF), and urine, as well as throughout all human tissues. Ammonia exists in all eukaryotes, ranging from yeast to humans. In humans, ammonia is involved in several metabolic pathways, some of which include glucose-alanine cycle, phenylalanine and tyrosine metabolism, homocysteine degradation, and d-arginine and d-ornithine metabolism. Ammonia is also involved in several metabolic disorders, some of which include ureidopropionase deficiency, hyperornithinemia-hyperammonemia-homocitrullinuria [hhh-syndrome], non ketotic hyperglycinemia, and beta-mercaptolactate-cysteine disulfiduria. Moreover, ammonia is found to be associated with 3-Hydroxy-3-methylglutaryl-CoA lyase deficiency, 3-Methyl-crotonyl-glycinuria, citrullinemia type I, and short bowel syndrome. Ammonia is a non-carcinogenic (not listed by IARC) potentially toxic compound. Ammonia or azane is a compound of nitrogen and hydrogen with the formula NH3. The simplest pnictogen hydride, ammonia is a colourless gas with a characteristic pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products . Acute Exposure: EYES: irrigate opened eyes for several minutes under running water. INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice. SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention. INHALATION: supply fresh air. If required provide artificial respiration. (z)-n-coumaroyl-5-hydroxyanthranilic acid is a member of the class of compounds known as avenanthramides. Avenanthramides are a group of phenolic alkaloids consisting of conjugate of three phenylpropanoids (ferulic, caffeic, or p-coumaric acid) and anthranilic acid (z)-n-coumaroyl-5-hydroxyanthranilic acid is practically insoluble (in water) and a weakly acidic compound (based on its pKa). (z)-n-coumaroyl-5-hydroxyanthranilic acid can be found in cereals and cereal products and oat, which makes (z)-n-coumaroyl-5-hydroxyanthranilic acid a potential biomarker for the consumption of these food products.
Hydrogen peroxide
Hydrogen peroxide (H2O2) is a very pale blue liquid that appears colourless in a dilute solution. H2O2 is slightly more viscous than water and is a weak acid. H2O2 is unstable and slowly decomposes in the presence of light. It has strong oxidizing properties and is, therefore, a powerful bleaching agent that is mostly used for bleaching paper. H2O2 has also found use as a disinfectant and as an oxidizer. H2O2 in the form of carbamide peroxide is widely used for tooth whitening (bleaching), both in professionally- and in self-administered products. H2O2 is a well-documented component of living cells and is a normal metabolite of oxygen in the aerobic metabolism of cells and tissues. A total of 31 human cellular H2O2 generating enzymes has been identified so far (PMID: 25843657). H2O2 plays important roles in host defence and oxidative biosynthetic reactions. At high levels (>100 nM) H2O2 is toxic to most cells due to its ability to non-specifically oxidize proteins, membranes and DNA, leading to general cellular damage and dysfunction. However, at low levels (<10 nM), H2O2 functions as a signalling agent, particularly in higher organisms. In plants, H2O2 plays a role in signalling to cause cell shape changes such as stomatal closure and root growth. As a messenger molecule in vertebrates, H2O2 diffuses through cells and tissues to initiate cell shape changes, to drive vascular remodelling, and to activate cell proliferation and recruitment of immune cells. H2O2 also plays a role in redox sensing, signalling, and redox regulation (PMID: 28110218). This is normally done through molecular redox “switches” such as thiol-containing proteins. The production and decomposition of H2O2 are tightly regulated (PMID: 17434122). In humans, H2O2 can be generated in response to various stimuli, including cytokines and growth factors. H2O2 is degraded by several enzymes including catalase and superoxide dismutase (SOD), both of which play important roles in keeping the amount of H2O2 in the body below toxic levels. H2O2 also appears to play a role in vitiligo. Vitiligo is a skin pigment disorder leading to patchy skin colour, especially among dark-skinned individuals. Patients with vitiligo have low catalase levels in their skin, leading to higher levels of H2O2. High levels of H2O2 damage the epidermal melanocytes, leading to a loss of pigment (PMID: 10393521). Accumulating evidence suggests that hydrogen peroxide H2O2 plays an important role in cancer development. Experimental data have shown that cancer cells produce high amounts of H2O2. An increase in the cellular levels of H2O2 has been linked to several key alterations in cancer, including DNA changes, cell proliferation, apoptosis resistance, metastasis, angiogenesis and hypoxia-inducible factor 1 (HIF-1) activation (PMID: 17150302, 17335854, 16677071, 16607324, 16514169). H2O2 is found in most cells, tissues, and biofluids. H2O2 levels in the urine can be significantly increased with the consumption of coffee and other polyphenolic-containing beverages (wine, tea) (PMID: 12419961). In particular, roasted coffee has high levels of 1,2,4-benzenetriol which can, on its own, lead to the production of H2O2. Normal levels of urinary H2O2 in non-coffee drinkers or fasted subjects are between 0.5-3 uM/mM creatinine whereas, for those who drink coffee, the levels are between 3-10 uM/mM creatinine (PMID: 12419961). It is thought that H2O2 in urine could act as an antibacterial agent and that H2O2 is involved in the regulation of glomerular function (PMID: 10766414). A - Alimentary tract and metabolism > A01 - Stomatological preparations > A01A - Stomatological preparations > A01AB - Antiinfectives and antiseptics for local oral treatment D - Dermatologicals > D08 - Antiseptics and disinfectants > D08A - Antiseptics and disinfectants S - Sensory organs > S02 - Otologicals > S02A - Antiinfectives > S02AA - Antiinfectives It is used in foods as a bleaching agent, antimicrobial agent and oxidising agent C254 - Anti-Infective Agent > C28394 - Topical Anti-Infective Agent D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides D000890 - Anti-Infective Agents
Hydrogen sulfide
Hydrogen sulfide, also known as h2s or acide sulfhydrique, is a member of the class of compounds known as other non-metal sulfides. Other non-metal sulfides are inorganic compounds containing a sulfur atom of an oxidation state of -2, in which the heaviest atom bonded to the oxygen belongs to the class of other non-metals. Hydrogen sulfide can be found in a number of food items such as small-leaf linden, agar, devilfish, and nutmeg, which makes hydrogen sulfide a potential biomarker for the consumption of these food products. Hydrogen sulfide can be found primarily in blood and feces, as well as throughout most human tissues. Hydrogen sulfide exists in all living species, ranging from bacteria to humans. In humans, hydrogen sulfide is involved in a couple of metabolic pathways, which include cysteine metabolism and cystinosis, ocular nonnephropathic. Hydrogen sulfide is also involved in beta-mercaptolactate-cysteine disulfiduria, which is a metabolic disorder. Moreover, hydrogen sulfide is found to be associated with hydrogen sulfide poisoning. Hydrogen sulfide is a non-carcinogenic (not listed by IARC) potentially toxic compound. Hydrogen sulfide often results from the microbial breakdown of organic matter in the absence of oxygen gas, such as in swamps and sewers; this process is commonly known as anaerobic digestion. H 2S also occurs in volcanic gases, natural gas, and in some sources of well water. The human body produces small amounts of H 2S and uses it as a signaling molecule . Treatment involves immediate inhalation of amyl nitrite, injections of sodium nitrite, inhalation of pure oxygen, administration of bronchodilators to overcome eventual bronchospasm, and in some cases hyperbaric oxygen therapy (HBO). HBO therapy has anecdotal support and remains controversial (L1139) (T3DB). Hydrogen sulfide is a highly toxic and flammable gas. Because it is heavier than air it tends to accumulate at the bottom of poorly ventilated spaces. Although very pungent at first, it quickly deadens the sense of smell, so potential victims may be unaware of its presence until it is too late. H2S arises from virtually anywhere where elemental sulfur comes into contact with organic material, especially at high temperatures. Hydrogen sulfide is a covalent hydride chemically related to water (H2O) since oxygen and sulfur occur in the same periodic table group. It often results when bacteria break down organic matter in the absence of oxygen, such as in swamps, and sewers (alongside the process of anaerobic digestion). It also occurs in volcanic gases, natural gas and some well waters. It is also important to note that Hydrogen sulfide is a central participant in the sulfur cycle, the biogeochemical cycle of sulfur on Earth. As mentioned above, sulfur-reducing and sulfate-reducing bacteria derive energy from oxidizing hydrogen or organic molecules in the absence of oxygen by reducing sulfur or sulfate to hydrogen sulfide. Other bacteria liberate hydrogen sulfide from sulfur-containing amino acids. Several groups of bacteria can use hydrogen sulfide as fuel, oxidizing it to elemental sulfur or to sulfate by using oxygen or nitrate as oxidant. The purple sulfur bacteria and the green sulfur bacteria use hydrogen sulfide as electron donor in photosynthesis, thereby producing elemental sulfur. (In fact, this mode of photosynthesis is older than the mode of cyanobacteria, algae and plants which uses water as electron donor and liberates oxygen). Hydrogen sulfide can be found in Alcaligenes, Chromobacteriumn, Klebsiella, Proteus and Pseudomonas (PMID: 13061742). D018377 - Neurotransmitter Agents > D064426 - Gasotransmitters D004785 - Environmental Pollutants > D000393 - Air Pollutants
3-Mercaptopyruvic acid
3-Mercaptopyruvic acid, also known as 3-mercapto-2-oxopropanoate or beta-thiopyruvate, belongs to the class of organic compounds known as alpha-keto acids and derivatives. These are organic compounds containing an aldehyde substituted with a keto group on the adjacent carbon. 3-Mercaptopyruvic acid is an intermediate in cysteine metabolism. 3-Mercaptopyruvic acid exists in all living organisms, ranging from bacteria to humans. Within humans, 3-mercaptopyruvic acid participates in a number of enzymatic reactions. In particular, 3-mercaptopyruvic acid and cyanide can be converted into pyruvic acid and thiocyanate; which is mediated by the enzyme 3-mercaptopyruvate sulfurtransferase. In addition, 3-mercaptopyruvic acid can be biosynthesized from 3-mercaptolactic acid; which is mediated by the enzyme L-lactate dehydrogenase. It has been studied as a potential treatment for cyanide poisoning, but its half-life is too short for it to be clinically effective. In humans, 3-mercaptopyruvic acid is involved in cystinosis, ocular nonnephropathic. Outside of the human body, 3-mercaptopyruvic acid has been detected, but not quantified in several different foods, such as lima beans, spinachs, shallots, mexican groundcherries, and white lupines. This could make 3-mercaptopyruvic acid a potential biomarker for the consumption of these foods. 3-mercaptopyruvic acid, also known as beta-mercaptopyruvate or beta-thiopyruvic acid, belongs to alpha-keto acids and derivatives class of compounds. Those are organic compounds containing an aldehyde substituted with a keto group on the adjacent carbon. 3-mercaptopyruvic acid is slightly soluble (in water) and a moderately acidic compound (based on its pKa). 3-mercaptopyruvic acid can be found in a number of food items such as garland chrysanthemum, rubus (blackberry, raspberry), tarragon, and arrowhead, which makes 3-mercaptopyruvic acid a potential biomarker for the consumption of these food products. 3-mercaptopyruvic acid exists in all living organisms, ranging from bacteria to humans. In humans, 3-mercaptopyruvic acid is involved in a couple of metabolic pathways, which include cysteine metabolism and cystinosis, ocular nonnephropathic. 3-mercaptopyruvic acid is also involved in beta-mercaptolactate-cysteine disulfiduria, which is a metabolic disorder. 3-Mercaptopyruvic acid is an intermediate in cysteine metabolism. It has been studied as a potential treatment for cyanide poisoning, but its half-life is too short for it to be clinically effective. Instead, prodrugs, such as sulfanegen, are being evaluated to compensate for the short half-life of 3-mercaptopyruvic acid .
Hydrogen cyanide
Hydrogen cyanide (with the historical common name of Prussic acid) is a chemical compound with chemical formula HCN. It is a colorless, extremely poisonous liquid that boils slightly above room temperature at 26 °C (79 °F). Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. A minor tautomer of HCN is HNC, hydrogen isocyanide. Hydrogen cyanide is weakly acidic with a pKa of 9.2. It partly ionizes in water solution to give the cyanide anion, CN. (Wikipedia) D009676 - Noxae > D011042 - Poisons > D002619 - Chemical Warfare Agents
Hydrogen Ion
Hydrogen ion, also known as proton or h+, is a member of the class of compounds known as other non-metal hydrides. Other non-metal hydrides are inorganic compounds in which the heaviest atom bonded to a hydrogen atom is belongs to the class of other non-metals. Hydrogen ion can be found in a number of food items such as lowbush blueberry, groundcherry, parsley, and tarragon, which makes hydrogen ion a potential biomarker for the consumption of these food products. Hydrogen ion exists in all living organisms, ranging from bacteria to humans. In humans, hydrogen ion is involved in several metabolic pathways, some of which include cardiolipin biosynthesis cl(i-13:0/a-25:0/a-21:0/i-15:0), cardiolipin biosynthesis cl(a-13:0/a-17:0/i-13:0/a-25:0), cardiolipin biosynthesis cl(i-12:0/i-13:0/a-17:0/a-15:0), and cardiolipin biosynthesis CL(16:1(9Z)/22:5(4Z,7Z,10Z,13Z,16Z)/18:1(11Z)/22:5(7Z,10Z,13Z,16Z,19Z)). Hydrogen ion is also involved in several metabolic disorders, some of which include de novo triacylglycerol biosynthesis TG(20:3(8Z,11Z,14Z)/22:6(4Z,7Z,10Z,13Z,16Z,19Z)/22:5(7Z,10Z,13Z,16Z,19Z)), de novo triacylglycerol biosynthesis TG(18:2(9Z,12Z)/20:0/20:4(5Z,8Z,11Z,14Z)), de novo triacylglycerol biosynthesis TG(18:4(6Z,9Z,12Z,15Z)/18:3(9Z,12Z,15Z)/18:4(6Z,9Z,12Z,15Z)), and de novo triacylglycerol biosynthesis TG(24:0/20:5(5Z,8Z,11Z,14Z,17Z)/24:0). A hydrogen ion is created when a hydrogen atom loses or gains an electron. A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle-free space. Due to its extremely high charge density of approximately 2×1010 times that of a sodium ion, the bare hydrogen ion cannot exist freely in solution as it readily hydrates, i.e., bonds quickly. The hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions . Hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions. Under aqueous conditions found in biochemistry, hydrogen ions exist as the hydrated form hydronium, H3O+, but these are often still referred to as hydrogen ions or even protons by biochemists. [Wikipedia])
Lanthionine
Lanthionine is a nonproteinogenic amino acid with the chemical formula (HOOC-CH(NH2)-CH2-S-CH2-CH(NH2)-COOH). It is typically formed by a cysteine residue and a dehydrated serine residue. Despite its name, lanthionine does not contain the element lanthanum. Lanthionine belongs to the class of organic compounds known as L-cysteine-S-conjugates. These are compounds containing L-cysteine where the thio-group is conjugated. Lanthionine is a uremic toxin (PMID: 30087103). In 1941, lanthionine was first isolated by treating wool with sodium carbonate. It was found to be a sulfur-containing amino acid; accordingly it was given the name lanthionine [wool (Latin: Lana), sulfur (Greek: theîon)].[1] Lanthionine was first synthesized by alkylation of cysteine with β-chloroalanine.[2] Lanthionines are found widely in nature. They have been isolated from human hair, lactalbumin, and feathers. Lanthionines have also been found in bacterial cell walls and are the components of a group of gene-encoded peptide antibiotics called lantibiotics, which includes nisin (a food preservative), subtilin, epidermin (effective against Staphylococcus and Streptococcus), and ancovenin (an enzyme inhibitor).[3][4] L-Lanthionine. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=922-55-4 (retrieved 2024-06-29) (CAS RN: 922-55-4). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).