What is "cobalamin"

n. (context organic compound English) Any of several forms of vitamin B12 depending on the upper axial ligand of the cobalt ion.

n. a B vitamin that is used to treat pernicious anemia [syn: vitamin B12, cyanocobalamin, antipernicious anemia factor]

Cobalamin may refer to several chemical forms of vitamin B, depending on the upper axial ligand of the cobalt ion. These are:

• Cyanocobalamin (R = –CN)
• Hydroxocobalamin (R = –OH)
• Methylcobalamin (R = –CH), an active form of vitamin B
• Adenosylcobalamin (R = –Ado), also an active form of vitamin B

Cobalamin is susceptible to acid. During its biosynthesis, complexes are formed that protect it.