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It can bind two different forms of the cobalamin cofactor, with cobalt bonded either to a methyl group (methylcobalamin) or to 5'-deoxyadenosine (adenosylcobalamin). Cobalamin-binding domains are mainly found in two families of enzymes present in animals and prokaryotes, which perform distinct kinds of reactions at the cobalt-carbon bond .
Animals, including humans, can convert cyanocobalamin to any one of the active vitamin B 12 compounds. [21] Cyanocobalamin is one of the most widely manufactured vitamers in the vitamin B 12 family (the family of chemicals that function as B 12 when put into the body), because cyanocobalamin is the most air-stable of the B 12 forms. [22]
Cyanocobalamin is the most common form used in dietary supplements and food fortification because cyanide stabilizes the molecule against degradation. Methylcobalamin is also offered as a dietary supplement. [12] There is no advantage to the use of adenosylcobalamin or methylcobalamin forms for the treatment of vitamin B 12 deficiency. [20] [21 ...
Methylcobalamin (mecobalamin, MeCbl, or MeB 12) is a cobalamin, a form of vitamin B 12. It differs from cyanocobalamin in that the cyano group at the cobalt is replaced with a methyl group. [1] Methylcobalamin features an octahedral cobalt(III) centre and can be obtained as bright red crystals. [2]
Treatment should take into account the cause and severity of the condition. [6] Treatment is done by vitamin B 12 supplementation, either by mouth or by injection. [3] Initially in high daily doses, followed by less frequent lower doses, as the condition improves. [3] If a reversible cause is found, that cause should be corrected if possible. [11]
In methylcobalamin the ligand is a methyl group, which is electrophilic. in vitamin B12, the alkyl ligand is an adenosyl group. Related to vitamin B12 are cobalt porphyrins, dimethylglyoximates, and related complexes of Schiff base ligands. These synthetic compounds also form alkyl derivatives that undergo diverse reactions reminiscent of the ...
Cyanocobalamin is usually converted to hydroxocobalamin in the serum, whereas hydroxocobalamin is converted to either methylcobalamin or adenosylcobalamin. Cobalamins circulate bound to serum proteins called transcobalamins (TC) and haptocorrins. Hydroxocobalamin has a higher affinity to the TC II transport protein than cyanocobalamin, or ...
The structure of vitamin B 12 was the first low-molecular weight natural product determined by x-ray analysis rather than by chemical degradation. Thus, while the structure of this novel type of complex biomolecule was established, its chemistry remained essentially unknown; exploration of this chemistry became one of the tasks of the vitamin's chemical synthesis.