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Kirk-Othmer Encyclopedia of Chemical Technology

Vitamin B₁₂

Standard Article

John W. Scott¹

¹Hoffmann-La Roche Inc.

DOI: 10.1002/0471238961.2209200119031520.a01
Article Online Posting Date: December 4, 2000

Abstract | Full Text: PDF (587K)

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Abstract

Vitamin B₁₂ is the generic name for a closely related group of substances of microbial origin. The compounds are octahedral cobalt corrin complexes varying primarily in one axial ligand. Vitamin B₁₂ functions as coenzyme in a number of rearrangement reactions, as well as in the methylation of homocysteine to methionine. A total synthesis of cyanocobalamin has been achieved. Commercial production, however, is entirely by fermentation of species such as Pseudomonas dentrificans.

Keywords: Structure; Vitamin B12; Occurrence; Biochemical function; Dietary sources; Methyl cobalamin; Adenosylcobalamin; Cyanocabalamin; Metabolism; Deficiency; Animal feeds