Newton, W. Austin (University of California, Berkeley), and Esmond E. Snell. Formation and interrelationships of tryptophanase and tryptophan synthetases in Escherichia coli. J. Bacteriol. 89:355-364. 1965.-In addition to the classical tryptophan-repressible tryptophan synthetase (TSase-tr), tryptophan auxotrophs of Escherichia coli contain another distinct tryptophan synthetase (TSase-ti) whic...

Cyclic guanosine 3',5'-monophosphate inhibits the synthesis of beta-galactosidase and tryptophanase in cultures of Escherichia coli growing in minimal media with glucose or glycerol as the carbon source. Cyclic guanosine 3',5'-monophosphate acts at the transcriptional level in the lac operon, it exerts its action at the promoter site of the operon, and requires the presence of functional cyclic...

d-Tryptophan was converted to l-tryptophan in tissue cultures of tobacco, in whole cells treated with dimethylsulfoxide, and in cell-free extracts treated by Sephadex G-25 filtration. Evidence was obtained that tryptophanase, tryptophan pyrrolase, and transaminase activities were not involved. The data were best explained by the presence of a tryptophan racemase as the enzyme catalyzing the rea...