Regulation of anthranilate synthase in Escherichia coli growing in glucose-limited chemostats

Strains of Escherichia coli isogenic except for the trpR locus were grown in glucose-limited chemostats. Anthranilate synthase was assayed spectrofluorimetrically to measure trp expression. The specific activity was about ten times greater in the trpR- strain than in the trpR+ strain. In glucose-limited chemostats, the specific activity of anthranilate synthase was independent of growth rate. Both strains produced two to three times more anthranilate synthase in chemostats than in batch culture. The addition of 19 amino acids (not including tryptophan) increased trp expression of anthranilate synthase fivefold in the trpR+ strain.