cyanocobalamin

(vitamin B12) A complex molecule consisting of a corrin ring (similar to a porphyrin ring) and a ribonucleotide. The corrin ring contains a cobalt atom, which is bonded to a cyanide group and to the ribonucleotide. Cyanocobalamin is not synthesized by plants or animals and commercial production is from bacterial cultures, e.g. of Streptomyces olivaceus. It is not needed by plants but animals need it for the normal development of erythrocytes.