Regulation of Phospho-2-keto-3-deoxy-heptonate Aldolase (DAHP Synthase) and Anthranilate Synthase of Pseudomonas aureofaciens

Institute of Microbiology, University of Hohenheim, Garbenstrasse 30, D-7000 Stuttgart 70, Federal Republic of Germany ABSTRACT Phospho-2-keto-3-deoxy-heptonate aldolase (DAHP synthase) of Pseudomonas aureofaciens ATCC 15926 was inhibited by L-tyrosine. The inhibition was competitive with erythrose 4-phosphate as the varied substrate but non-competitive with respect to phosphoenol-pyruvate. Anthranilate synthase was inhibited by L-tryptophan. The inhibition was competitive with respect to chorismate but non-competitive with L-glutamine or NH 4 + as the varied substrate. DAHP synthase and anthranilate synthase were not repressed when aromatic amino acids were included in the growth medium. In bacteria grown in the presence of L-phenylalanine, the anthranilate synthase activity was enhanced about threefold compared with the control. Similar results were obtained with the mutant strain P. aureofaciens ACN, which produces increased amounts of pyrrolnitrin.