Vitamin B12

vitamin involved in the metabolism of every cell

Cyanocobalamin is a form of vitamin used to treat and prevent vitamin deficiency except in the presence of cyanide toxicity. The deficiency may occur in pernicious anemia, following surgical removal of the stomach, with fish tapeworm, or due to bowel cancer. It is given by mouth, by injection into a muscle, or as a nasal spray.

vitamin metabolic disorder that results from low blood levels of vitamin B12

Hydroxocobalamin, also known as vitamin B12a and hydroxycobalamin, is a vitamin found in food and used as a dietary supplement. As a supplement it is used to treat vitamin B12 deficiency including pernicious anemia. Other uses include treatment for cyanide poisoning, Leber's optic atrophy, and toxic amblyopia. It is given by injection into a muscle or vein, by pill or sublingually.

Methylcobalamin (mecobalamin, MeCbl, or MeB) is a cobalamin, a form of vitamin B. It differs from cyanocobalamin in that the cyano group at the cobalt is replaced with a methyl group. Methylcobalamin features an octahedral cobalt(III) centre and can be obtained as bright red crystals. From the perspective of coordination chemistry, methylcobalamin is notable as a rare example of a compound that contains metal–alkyl bonds. Nickel–methyl intermediates have been proposed for the final step of methanogenesis.

Adenosylcobalamin (AdoCbl), also known as coenzyme B12, cobamamide, and dibencozide, is one of the biologically active forms of vitamin B12. class=skin-invert-image|left|thumb|Schematic diagram of the propionate metabolic pathway. Adenosylcobalamin is required as a coenzyme by the methylmalonyl-CoA mutase in order to convert L-methylmalonyl-CoA into succinyl-CoA, otherwise methylmalonic acid accumulates. Adenosylcobalamin participates as a cofactor in radical-mediated 1,2-carbon skeleton rearrangements. These processes require the formation of the deoxyadenosyl radical through homolytic dissoc

medical test for patients with vitamin B12 deficiency

Transcobalamins are carrier proteins which bind cobalamin (vitamin B12).