Stable isotope studies on the biosynthesis of the thiazole moiety of thiamin in Escherichia coli.

Deuterated and 13C-labeled sugars were fed to Escherichia coli growing on defined medium. The position and extent of incorporation of the label into the 4-methyl-5-beta-hydroxyethylthiazole portion of thiamin and other cellular components were measured by gas chromatography-mass spectrometry. Based on the findings, it is concluded that the contiguous five-carbon unit of the 4-methyl-5-beta-hydroxyethylthiazole is biosynthetically derived from pyruvate and a triose phosphate.