Hydroxamate formation by anthranilate synthetase of Escherichia coli K12.

HO' H /H2 0 \ I dOOH chorismic acid anthranilic acid (Gibson and Gibson, 1964; Somerville, unpublished results). In Escherichia coli the catalytically active species is a protein complex formed by aggregation of the products of the E and D genes of the tryptophan operon (Ito and Yanofsky, 1966). Anthranilate synthetase is one of a class of amidotransferase enzymes where L-glutamine serves as the physiological nitrogen donor (Meister, 1962). Ammonia, added at relatively high concentrations, will serve as the nitrogen source for anthranilate formation in vitro (Srinivasan and Rivera, 1963; Edwards et al., -1964). Ammonia is also active in vivo (Gibson et al., 1967). -Although the overall reaction leading from chorismate to anthranilate has been studied (Baker and Crawford, 19671, neither the structures of possible intermediates between chorismate and