BIOSYNTHESIS OF COBALAMIN ANALOGUES BY PROPIONIBACTERIUM ARABINOSUM

Abstract

Examination by filter paper partition chromatography and filter paper iono-phoresis of the cobalamins present in cultures of Propionibacterium arabinosum grown in a medium containing glucose, yeast extract, and salts showed that only adenine-hydroxo-cobalamin was present. Addition of 5 6-dimethylbenzimidazole to the growing cultures resulted in formation of a cobalamin containing this substance in the nucleotide portion of the molecule. Cobalamins containing benzimidazole, 5-methylbenzimidazole, 2,6-diaminopurine, benzotriazole, benzothiazole, and 5-nitrobenzimidazole in the nucleotide were prepared by this procedure and found to have the migration and biological characteristics of these cobalamins as previously described in the literature. New cobalamins have also been prepared presumably including those containing 5-trifluoromethylbenzimidazole, phenazine, 2-hydroxyphenazine, 4-bromo-6-methoxybenzimidazole, 3,4-dihydro-4-oxoquinazoline, 4-chloro-8-nitroquinazoline, and quinoxaline in the nucleotide. All of these new cobalamins were found to stimulate the growth of cobalamin-requiring cultures of Escherichia coli, Lactobacillus leichmannii, and Ochromonas malhamensis.