Inhibition of 3-deoxy-d-arabinoheptulosonic acid-7-phosphate synthetase (trp) in Escherichia coli.

The growth of a strain of Escherichia coli K-12 which possesses only the single isoenzyme 3-deoxy-d-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase (trp), and which makes this enzyme constitutively, is inhibited by tryptophan. The accumulation of DAHP by a derivative of this strain unable to convert DAHP to dehydroquinate is also inhibited by tryptophan. The enzymic activity of DAHP synthetase (trp) in the presence of CO(2+) is sensitive to inhibition by tryptophan. Mutant strains of E. coli have been isolated in which DAHP synthetase (trp) is feedback-resistant.