STUDIES ON THIAMINE BIOSYNTHESIS BY ESCHERICHIA COLI : (IV) INCORPORATION OF RADIOACTIVE CARBON OF ASPARTATE-2-^<14>C AND FORMATE-^<14>C INTO THE PYRIMIDINE MOIETY OF THIAMINE

Abstract

The incorporation of radioactive carbon from DL-aspartate-2-^<14>C and Na-formate-^<14>C into the pyrimidine moiety of thiamine was investigated by isolation of thiamine produced by a mutant strain (thiazole-less, 26-43) of Escherichia coli growing in culture media supplemented with thiazole. IRC-50 column chromatography, conversion of thiamine to thiochrome, repeated paper chromatography and actigraphy were devised for the separation and isolation of thiamine in the tracer studies. The incorporation of radioactive carbon from the both ^<14>C-compounds was demonstrated by detection of radioactivity corresponding to the fluorescent spot of thiochrome on paperchromatogram. From the comparison of specific radioactivities of thiochrome isolated and those of ^<14>C-compounds added, aspartate-2-^<14>C is incorporated to a better extent than formate-^<14>C.