Tryptophanase-tryptophan synthetase systems in Escherichia coli. III. Requirements for enzyne synthesis.

Freundlich, Martin (University of Minnesota, Minneapolis) and Herman C. Lichstein. Tryptophanase-tryptophan synthetase systems in Escherichia coli. III. Requirements for enzyme synthesis. J. Bacteriol. 84:996-1006. 1962.-The requirements for the formation of tryptophanase and tryptophan synthetase in Escherichia coli during repression release were studied. The kinetics of the formation of tryptophan synthetase differed in the two strains examined; this was attributed to differences in the endogenous level of tryptophan in the bacterial cells. The formation of both enzymes was inhibited by chloramphenicol, and by the absence of arginine in an arginine-requiring mutant. These results are indicative of a requirement for protein synthesis for enzyme formation. Requirements for nucleic acid synthesis were examined by use of a uracil- and thymine-requiring mutant, and with purine and pyrimidine analogues. The results obtained suggest that some type of ribonucleic acid synthesis was necessary for the formation of tryptophanase and tryptophan synthetase.