STUDIES ON BIOLOGICAL FUNCTIONS OF 5'-METHYLTHIOADENOSINE VITAMIN B₁₂-REPLACING EFFECT FOR OCHROMONAS MALHAMENSIS

Abstract

An unidentified factor which can completely replace the vitamin B₁₂ requirement of a protozoan, Ochromonas malhamensis, was found in commercial yeast extract powder. The factor showed a positive sugar test with orcinol reagent. The presence of sulfur was demonstrated with platinic iodide reagent. The molecular weight, 297, and the chemical formula, C₁₁H₁₅O₃N₅S, were determined by mass spectrometry and elemental analysis. Infra-red and nuclear magnetic resonance studies indicated the presence of a thiomethyl group. The factor was hydrolyzed by treatment with acid into adenine and 5-methylthioribose, i.e., the sugar constituent of 5'-methylthioadenosine. The factor was identified as 5'methylthioadenosine from the behavior exhibited in thin-layer chromatography and from microbiological tests for its vitamin B₁₂-replacing effect.