Abstract
The growth of Escherichia coli is inhibited by aminothiazole added to the medium which inhibits the enzymatic synthesis of thiamine by competing with thiazole as substrate in the enzyme system that catalyzes the condensation of hydroxymethylpyrimidine and thiazole. Therefore, by estimating the activities of various amino acids added to the medium to reverse the growth inhibition, some plausible thiazole precursors were surveyed. L-Methionine was effective on the reverse of the growth inhibition at 1×10^<-6>M, whereas cysteine and cystine were less effective. L-Glutamic acid and L-asparic acid also had some accerelating activities on the growht of E. coli inhibited by aminothiazole. In addition the coexistence of L-methionine and L-glutamic aicd showed a multiplied aciton on the reverse of the inhibition which suggested possible intermediates in the biosynthesis of thiazole moiety of thiamine.
