Isolation and identification of 5-methylthioribose from Escherichia coli B

5-Methylthioribose was isolated after incubation of Escherichia coli B in a glucose-salts medium. At least 60% of the radioactivity in absolute ethanol extracts of the residue from lyophilized medium supplemented with ³⁵SO₄²⁻ was located in two chromatographic areas that were identified as 5-methylthioribose and its sulfoxide. The sulfoxide was formed by oxidation of 5-methylthioribose during necessary processing of cultures and fractions. These compounds were characterized by functional group analysis and chromatographic comparison with authentic material. 5-Methylthioribose sulfoxide was isolated from 12 l of incubation medium of E. coli. After purification in three paper and one thin-layer chromatographic systems, 50 μg was obtained. The trimethylsilyl derivative of this compound was compared with that of authentic 5-methylthioribose sulfoxide. Gas chromatography and mass spectrometry confirmed the identity. This is the first report of 5-methylthioribose from a bacterium.