Production of aromatic acids by microorganisms. VII. Regulatory properties of anthranilate synthetase from Corynebacterium glutamicum.

Abstract

Anthranilate synthetase from Corynebacterium glutamicum ATCC 13032 was studied using the dialyzed cell-free extract. The reaction mechanism of the enzyme was found to be of ping-pong type. The Km values for chorismate and L-glutamine were 4.8×10-5M and 5.9×10-3M, respectively. Enzyme activity was strongly inhibited by L-tryptophan competitively with respect to chorismate and noncompetitively with respect to L-glutamine. This competitive inhibition of anthranilate synthetase activity by L-tryptophan means that the enzyme reaction would proceed in the condition under which sufficient amount of chorismate is supplied and explains rationally the excretion of L-tryptophan and anthranilate by a phenylalanine and tyrosine double auxotroph of C. glutamicum, KY 9456, in the medium supplemented with limiting amounts of L-phenylalanine and L-tyrosine. Formation of anthranilate synthetase in C. glutamicum KY 9285, a tryptophan auxotroph, was sensitive to the repression by L-tryptophan.