Abstract
In order to obtain the information on the precursor of the pyrimidine moiety of thiamine, the effect of amino acids and some other compounds on the production of thiamine of thiamine requiring mutant of E. coli (thiazole-less, 26-43) was investigated. The thiamine synthesis per growth of the mutant in culture media reduced with glucose and nitrogen sources are presumed to depend on the synthesis of pyrimidine by addition of the test materials, since the growth could be satisfied by the thiazole supplemented. The production of thiamine in overnight cultivation without shaking was increased by addition of aspartate, glutamate, histidine or oxaloacetate, fumarate and malate, respectively. By incubation of the cell suspensions for 2 hours on a rotatory shaker, thiamine synthesis was stimulated by addition of aspartate while other amino acids gave no significant stimulation. Maximal production was achieved with the combination of aspartate aad alanine. Further addition of pyruvate or fumarate was also effective. Increase of glucose in the medium depressed the thiamine synthesis by the cells. The resting cell expriments gave no significant effect by addition of such stimulators.
