Mono-Substituted Vit. B12 Amides. I. A Microbiological Study.

Abstract

Summary The methylamide, ethylamide, and anilide of the monocarboxylic acid of Vit. B₁₂ were inactive as B₁₂-antagonists despite their previous designation as “anti-Vit. B₁₂'substances. They satisfied the B₁₂ requirement of E. gracilis and L. leichmannii, but not that of E. coli and O. malhamensis. Combinations of sub-optimal levels of methionine plus methylamide, or ethylamide, gave greater growth of E. coli than this level of methionine alone. Addition of amide to Vit. B₁₂ neither inhibited nor enhanced growth over that with B₁₂ alone.