Classification Term: 669
Cobalamin derivatives (ontology term: CHEMONTID:0000352)
Organic compounds containing a corrin ring, a cobalt atom, an a nucleotide moiety. Cobalamin Derivatives are actually derived from vitamin B12." []
found 8 associated metabolites at category metabolite taxonomy ontology rank level.
Ancestor: Corrinoids
Child Taxonomies: There is no child term of current ontology term.
Cyanocobalamin
C63H89CoN14O14P (1355.5751964)
Cyanocobalamin (commonly known as Vitamin B12) is the most chemically complex of all the vitamins. Cyanocobalamins structure is based on a corrin ring, which, although similar to the porphyrin ring found in heme, chlorophyll, and cytochrome, has two of the pyrrole rings directly bonded. The central metal ion is Co (cobalt). Cyanocobalamin cannot be made by plants or by animals, as the only type of organisms that have the enzymes required for the synthesis of cyanocobalamin are bacteria and archaea. Higher plants do not concentrate cyanocobalamin from the soil and so are a poor source of the substance as compared with animal tissues. Cyanocobalamin is naturally found in foods including meat (especially liver and shellfish), eggs, and milk products. Antipernicious anaemia factor isolated from liver extracts; now obtained comly. from fermentation liquors of Streptomyces griseus and other microorganisms, e.g. Propionibacterium shermanii, Pseudomonas denitrificans. Nutrient, dietary supplement, stabiliser. Haematopoietic vitamin [DFC]
Adenosylcobalamin
C72H100CoN18O17P (1578.658308)
Adenosylcobalamin is one of two metabolically active forms synthesized upon ingestion of vitamin B12 and is the predominant form in the liver; it acts as a coenzyme in the reaction catalyzed by methylmalonyl-CoA mutase. A cobalamin (cbl) derivative in which the substituent is deoxyadenosyl. It is one of two metabolically active forms synthesized upon ingestion of vitamin B12 and is the predominant form in the liver; it acts as a coenzyme in the reaction catalyzed by methylmalonyl-CoA mutase (MCM; E.C. 5.4.99.2). Inborn errors of vitamin B12 metabolism are autosomal recessive disorders and have been classified into nine distinct complementation classes. Disorders affecting adenosylcobalamin cause methylmalonic acidemia and metabolic acidosis. Methylmalonyl-CoA mutase catalyzes the conversion of L-methylmalonyl-CoA to succinyl-CoA and uses adenosylcobalamin (AdoCbl) as a cofactor. Cbl must be transported into mitochondria, reduced and adenosylated before it can be utilized by MCM. (PMID: 17011224). Adenosylcobalamin is one of two metabolically active forms synthesized upon ingestion of vitamin B12 and is the predominant form in the liver; it acts as a coenzyme in the reaction catalyzed by methylmalonyl-CoA mutase. A cobalamin (cbl) derivative in which the substituent is deoxyadenosyl. It is one of two metabolically active forms synthesized upon ingestion of vitamin B12 and is the predominant form in the liver; it acts as a coenzyme in the reaction catalyzed by methylmalonyl-CoA mutase (MCM; E.C. 5.4.99.2).
Cobalamin
C62H88CoN13O14P (1328.5642978)
Cobalamin participates in two enzymatic processes in mammalian cells. In the methionine synthase (EC 2.1.1.13) reaction, homocysteine (HCys) is converted to methionine allowing for the "recycling" of 5-methyl-tetrahydrofolate (THF) to N5,10 methylene-THF which is needed for the de novo synthesis of thymidylic acid and ultimately, for DNA formation. Since conversion of N5,10-methylene-THF to N5-methyl-THF is irreversible, cobalamin deficiency "traps" folic acid as N5-methyl-THF. Concurrently, HCys accumulates while methionine decreases, leading to a decrease in S-adenosylmethionine which further limits N5,10-methylene-THF formation by decreasing the synthesis of formyl-THF ("formate starvation"). Decreased methionine and S-adenosylmethionine may limit many methylation reactions including those involving DNA and myelin basic protein. In the methylmalonyl CoA mutase (EC 5.1.99.1) reaction, methylmalonyl CoA, derived from propionic acid synthesized by intestinal bacteria, is converted to succinyl CoA, a precursor for fatty acid and heme synthesis Thus, cobalamin deficiency results in methylmalonic acid (MMA) accumulation. Cobalamin deficiency causes megaloblastic anemia and neurocognitive abnormalities but effects on immune function and bone formation have also been described. Low serum cobalamin levels increase the risk of osteoporosis. Tests for cobalamin deficiency include measurements of 1) total cobalamin; 2) MMA and HCys, as indices of functional cobalamin deficiency; and 3) holotranscobalamin as a measure of the metabolically active fraction of circulating cobalamin. Each approach has significant limitations. Moreover, since the pathogenesis of neurologic dysfunction in cobalamin deficiency remains unclear, these tests may not be reliable markers of neurocognitive impairment. Subtle cobalamin deficiency, defined as elevated metabolite levels usually in asymptomatic patients with low or normal serum cobalamin values, is prevalent in the elderly and has been associated with food cobalamin malabsorption, a disorder characterized by the inability to release vitamin B12 from food or from its binding proteins. Malabsorption is often unrecognized or not investigated. However, because of the potential seriousness of the complications, particularly neuropsychiatric and hematological investigation of all patients who present with vitamin or nutritional deficiency is required. Classic disorders, such as pernicious anemia, are the cause of cobalamin deficiency in only a limited proportion of elderly patients. Epidemiological studies have shown a prevalence of cobalamin deficiency of around 20\\% in the elderly population of industrialized countries (between 50\\% and 60\\%, depending on the definition of cobalamin deficiency used in the study). New routes of cobalamin administration (oral and nasal) are currently being developed, especially the use of oral cobalamin therapy to treat food-cobalamin malabsorption. (PMID: 16814909, 17822656) [HMDB]. Cobalamin is found in many foods, some of which are yellow bell pepper, green zucchini, sunburst squash (pattypan squash), and yellow wax bean. Cobalamin participates in two enzymatic processes in mammalian cells. In the methionine synthase (EC 2.1.1.13) reaction, homocysteine (HCys) is converted to methionine allowing for the "recycling" of 5-methyl-tetrahydrofolate (THF) to N5,10 methylene-THF which is needed for the de novo synthesis of thymidylic acid and ultimately, for DNA formation. Since conversion of N5,10-methylene-THF to N5-methyl-THF is irreversible, cobalamin deficiency "traps" folic acid as N5-methyl-THF. Concurrently, HCys accumulates while methionine decreases, leading to a decrease in S-adenosylmethionine which further limits N5,10-methylene-THF formation by decreasing the synthesis of formyl-THF ("formate starvation"). Decreased methionine and S-adenosylmethionine may limit many methylation reactions including those involving DNA and myelin basic protein. In the methylmalonyl CoA mutase (EC 5.1.99.1) reaction, methylmalonyl CoA, derived from propionic acid synthesized by intestinal bacteria, is converted to succinyl CoA, a precursor for fatty acid and heme synthesis Thus, cobalamin deficiency results in methylmalonic acid (MMA) accumulation. Cobalamin deficiency causes megaloblastic anemia and neurocognitive abnormalities but effects on immune function and bone formation have also been described. Low serum cobalamin levels increase the risk of osteoporosis. Tests for cobalamin deficiency include measurements of 1) total cobalamin; 2) MMA and HCys, as indices of functional cobalamin deficiency; and 3) holotranscobalamin as a measure of the metabolically active fraction of circulating cobalamin. Each approach has significant limitations. Moreover, since the pathogenesis of neurologic dysfunction in cobalamin deficiency remains unclear, these tests may not be reliable markers of neurocognitive impairment. Subtle cobalamin deficiency, defined as elevated metabolite levels usually in asymptomatic patients with low or normal serum cobalamin values, is prevalent in the elderly and has been associated with food cobalamin malabsorption, a disorder characterized by the inability to release vitamin B12 from food or from its binding proteins. Malabsorption is often unrecognized or not investigated. However, because of the potential seriousness of the complications, particularly neuropsychiatric and hematological investigation of all patients who present with vitamin or nutritional deficiency is required. Classic disorders, such as pernicious anemia, are the cause of cobalamin deficiency in only a limited proportion of elderly patients. Epidemiological studies have shown a prevalence of cobalamin deficiency of around 20\\% in the elderly population of industrialized countries (between 50\\% and 60\\%, depending on the definition of cobalamin deficiency used in the study). New routes of cobalamin administration (oral and nasal) are currently being developed, especially the use of oral cobalamin therapy to treat food-cobalamin malabsorption. (PMID: 16814909, 17822656).
Glutathionylcobalamin
Potentially one of the biologically important forms of Vitamin B12; formed rapidly from aquacobalamin [HMDB] Potentially one of the biologically important forms of Vitamin B12; formed rapidly from aquacobalamin;.
Methylcobalamin
C63H91CoN13O14P (1343.5877716)
The name vitamin B12 is used in two different ways. In a broad sense it refers to a group of cobalt-containing compounds known as cobalamins - cyanocobalamin (an artifact formed as a result of the use of cyanide in the purification procedures), hydroxocobalamin and the two coenzyme forms of B12, methylcobalamin (MeB12) and 5-deoxyadenosylcobalamin (adenosylcobalamin - AdoB12). In a more specific way, the term B12 is used to refer to only one of these forms, cyanocobalamin, which is the principal B12 form used for foods and in nutritional supplements. B12 cannot be made by plants or by animals, as the only type of organisms that have the enzymes required for the synthesis of B12 are bacteria and archaea. The total synthesis of B12 was reported in 1973 by Robert Burns Woodward, and remains one of the classic feats of total synthesis. Cyanocobalamin is a vitamin commonly known as vitamin B12 (or B12 for short). The name vitamin B12 is used in two different ways. In a broad sense it refers to a group of cobalt-containing compounds known as cobalamins - cyanocobalamin (an artifact formed as a result of the use of cyanide in the purification procedures), hydroxocobalamin and the two coenzyme forms of B12, methylcobalamin (MeB12) and 5-deoxyadenosylcobalamin (adenosylcobalamin - AdoB12). In a more specific way, the term B12 is used to refer to only one of these forms, cyanocobalamin, which is the principal B12 form used for foods and in nutritional supplements. Methylcobalamin (CH3-B12), a cobalamin, is a form of vitamin B12.
Hydroxocobalamin
C62H89CoN13O15P (1345.5670374000001)
Hydroxocobalamin, also known as hydroxycobalamin or vitamin B12a is a member of the class of compounds known as cobalamin derivatives. These organic compounds contain a corrin ring, a cobalt atom, and a nucleotide moiety. More specifically, cobalamins are characterized by a porphyrin-like corrin nucleus that contains a single cobalt atom bound to a benzimidazolyl nucleotide and a variable residue (R) group. The variable R group gives rise to the four most commonly known cobalamins: cyanocobalamin, methylcobalamin, 5-deoxyadenosylcobalamin, and hydroxycobalamin. Hydroxocobalamin is found in all living organisms ranging from microbes to plants to animals. However, it is only synthesized in microbes and plants. As humans cannot make hydroxocobalamin, it is required in the diet, making it an essential nutrient (i.e. a vitamin). Vitamin B12 is more abundant in animal products, especially meat, fish, eggs and dairy products although it is found in all fruits and vegetables in lower concentrations. In the serum, hydroxocobalamin and cyanocobalamin are believed to function as storage or transport forms of vitamin B12, whereas methylcobalamin and 5-deoxyadenosylcobalamin are the active forms of the coenzyme required for cell growth and replication. Hydroxocobalamin is often called vitamin B12 and is the natural form of vitamin B12, however, vitamin B12 refers to a group of cobalamins that are available in the human body in a variety of mostly interconvertible forms. Together with folate, cobalamins are essential cofactors required for DNA synthesis in cells where chromosomal replication and division are occurring. Cyanocobalamin is usually converted to hydroxocobalamin in the serum, whereas hydroxocobalamin is converted to either methylcobalamin or 5-deoxyadenosyl cobalamin. Cobalamins circulate bound to serum proteins called transcobalamins (TC) and haptocorrins. As a supplement hydroxocobalamin is used to treat vitamin B12 deficiency including pernicious anemia. It is also used in the prevention and treatment of vitamin B12 deficiency arising from alcoholism, malabsorption, tapeworm infestation, celiac disease, hyperthyroidism, hepatic-biliary tract disease, persistent diarrhea, ileal resection, pancreatic cancer, renal disease, prolonged stress, vegan diets, macrobiotic diets, and other restrictive diets. Other uses include treatment for cyanide poisoning, Lebers optic atrophy, and toxic amblyopia. Hydroxocobalamin is practically insoluble in water. Hydroxocobalamin was first isolated in 1949. It is on the World Health Organizations List of Essential Medicines, the most effective and safe medicines needed in a health system. Hydroxocobalamin is available as a generic medication. The wholesale cost in the developing world is about 0.12 To 0.84 USD per dose. Commercially, it is made from one of a number of different types of bacteria. Vitamin (haematopoietic)
Aquacobalamin
Aquacobalamin is one of the major forms of vitamin B(12) isolated from mammalian cells. Aquacobalamin and the thiolate forms of glutathione are the precursors of glutathionylcobalamin (GSCbl, a precursor to the formation of the two coenzyme forms of vitamin B(12), adenosylcobalamin and methylcobalamin) in mammalian cells. Under biological conditions the formation of GSCbl from aquacobalamin and glutathione is essentially irreversible; upon entering cells, any free (protein-unbound) aquacobalamin could be rapidly and irreversibly converted to GSCbl. (PMID: 15476387). Aquacobalamin is reduced to cob(II)alamin by Methionine synthase reductse (MSR) in the presence of NADPH, and this reduction leads to stimulation of the conversion of apomethionine synthase and aquacobalamin to methionine synthase holoenzyme. MSR serves as a special chaperone for human methionine synthase and as an aquacobalamin reductase, rather than acting solely in the reductive activation of methionine synthase. (PMID: 16769880). Aquacobalamin is one of the major forms of vitamin B(12) isolated from mammalian cells. Aquacobalamin and the thiolate forms of glutathione are the precursors of glutathionylcobalamin (GSCbl, a precursor to the formation of the two coenzyme forms of vitamin B(12), adenosylcobalamin and methylcobalamin) in mammalian cells. Under biological conditions the formation of GSCbl from aquacobalamin and glutathione is essentially irreversible; upon entering cells, any free (protein-unbound) aquacobalamin could be rapidly and irreversibly converted to GSCbl. (PMID: 15476387)
Cob(II)alamin
C62H89CoN13O14P (1329.5721224)
Cob(II)alamin is the product of the reduction catalyzed by microsomal cob(III)alamin reductase (PMID: 8507652). It binds to human methionine synthase (PMID: 1744096). Cob(II)alamin is the product of reduction catalyzed by the microsomal enzyme.