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M FREUNDLICH

Publications and source records attributed to M FREUNDLICH.

9 recordsLinked to original sources
PubMed1962

Tryptophanase-tryptophan synthetase systems in Escherichia coli. I. Effect of tryptophan and related compounds.

Freundlich, Martin (University of Minnesota, Minneapolis) and Herman C. Lichstein. Tryptophanase-tryptophan synthetase systems in Escherichia coli. I. Effect of tryptophan and related compounds. J. Bacteriol. 84:979-987. 1962.-The effect of tryptophan and related compounds on tryptophanase and tryptophan synthetase formation in Escherichia coli was determined. Several of these compounds stimulated the formation of tryptophanase while concomitantly decreasing the production of synthetase. A number of tryptophan analogues were found to inhibit growth. The possible mode of action of these substances was examined further. 5-Hydroxytryptophan greatly inhibited the formation of synthetase and also reduced growth. Its inhibitory action on growth was attributed, at least partially, to the false feedback inhibition of anthranilic acid formation. Tryptamine was found to be a potent inhibitor of the activity of synthetase, as well as of the enzyme(s) involved in the synthesis of anthranilic acid from shikimic acid. However, growth reduction was only partially reversed by tryptophan. Indole-3-acetic acid and indole-3-propionic acid decreased growth and increased the formation of synthetase six- to eightfold. The action of these compounds was ascribed to their ability to block the endogenous formation of tryptophan.

Escherichia coli↗
PubMed1962

Tryptophanase-tryptophan synthetase systems in Escherichia coli. II. Effect of glucose.

Freundlich, Martin (University of Minnesota, Minneapolis) and Herman C. Lichstein. Tryptophanase-tryptophan synthetase systems in Escherichia coli. II. Effect of glucose. J. Bacteriol. 84:988-995. 1962.-The effect of glucose and other compounds on the formation of tryptophanase and tryptophan synthetase in Escherichia coli was examined. Although most of these compounds were potent inhibitors of the synthesis of tryptophanase, they invariably increased the formation of tryptophan synthetase. The severity of tryptophanase inhibition depended upon the degree of utilization of the compound by the growing bacterial cells. It was found that high levels of tryptophan overcame by 40% the repression caused by glucose. The stimulatory effect of glucose on tryptophan synthetase formation in E. coli 9723E could be duplicated by indole-3-propionic acid. A study of the amino acid pool of E. coli 9723E revealed no free tryptophan in cells harvested from the basal medium containing glucose. In contrast, cells grown in the absence of glucose possessed a measurable amount of this amino acid. The possible mechanisms of the effect of glucose and related compounds on tryptophanase and tryptophan synthetase formation, as well as the relationship of these effects to the metabolic control of tryptophan metabolism, are discussed.

Escherichia coli↗
PubMed1962

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.

Chloramphenicol↗