Ochromonas malhamensis, vitamin

Knowledge of the coenzyme forms of vitamin Bi2 has increased steadily. The first coenzyme of Bi2 isolated from bacteria had similarities to pseudovitamin Bi2 it contained adenylic acid instead of 5,6-dimethyl-benzimidazole, but differed in lacking cyanide and having an extra molecule of adenine which was assumed to be bound to the cobalt atom by the coordination site, often occupied by cyanide (B24). This coenzyme, adenylcobamide, was completely inactive for Ochromonas malhamensis, but active for Escherichia coli 113-3. 

Ochromonas malhamensis responds to vitamin Bi2, but not to pseudovitamin Bi2 E. coli responds to both forms. Later other coenzymes were isolated (B25). One contained benzimidazole (BC), the other... 

F2. Ford, J. E., Microbiological assay of vitamin B12. The specificity of the requirement of Ochromonas malhamensis for cyanocobalamin. Brit. J. Nutrition 7, 299-306 (1953). 

Kl. Kamikubo, J., and Oguni, Y., Microbiological determination of vitamin B12 with Ochromonas malhamensis. J. Vitaminol. 5, 51-60 (1959). 

This compound is probably unique among the naturally occurring vitamin Bu-like compounds so far known in that it is active against pernicious anemia and for the chick (Bernhauer, 1955) and the flagellate Ochromonas malhamensis (Table II) (a microorganism which, as mentioned earlier, displays a specificity for vitamin Bw similar to that of birds and mammals (Ford, 1953)) as well as for E. coli and L. leichmannii. The chromatographic and ionophoretic properties illustrated in Fig. 1, with the other physical properties given by Friedrich and Bernhauer (1953), clearly differentiate Factor III from the cobalamins and from the other vitamin Bir-like factors. Its chemical relationship to these other compounds has not yet been established. 

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