title: Substances with biological activity of vitamin B12 formed during cultivation of Propionibacterium freudenreichii in the presence of precursors (short communications).
abstract: The papers of Kolhouse et al. and Cooper et al. described the occurrence of vitamin B12 analogues of unknown origin in blood serum. Some of these analogues may be derived from slaughter cattle raised on feed supplemented with vitamins and minerals, as was observed by Allen. Herbert et al. found vitamin B12 analogues in multivitamin preparations produced in U.S.A., and Kanazawa et al. in human liver, red cells and brain. It is not clear so far, if and how do vitamin B12 analogues interfere with vitamin B12 metabolism. When P. freudenreichii was cultivated in the presence of o-phenylenediamine and 5,6-dimethylbenzimidazole, which may be considered precursors as well as antimetabolites of vitamin B12, the stimulation of biosynthesis of substances with biological activity of vitamin B12 took place. Various signs show that these substances are probably vitamin B12 analogues. During stimulated and nonstimulated production of vitamin B12 by P. freudenreichii, two substances with vitamin B12 biological activity have always been obtained. Their relation was not stable and differed according to the conditions of cultivation. Every attempt to stimulate the biosynthesis of vitamin B12 resulted in the suppression of production of the substance with higher molecular weight, even if the biosynthesis of cobalamin (lower molecular weight) was increased. In our note we want to pay attention to the character of substances arising in the stimulated biosynthesis.
mesh_terms: D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D011424:Propionibacterium / Q000378:metabolism*; D014805:Vitamin B 12 / Q000096:biosynthesis* / Q000494:pharmacology
chemical_list: D014805:Vitamin B 12