Requires Mg2+. The reaction occurs in the reverse direction to that shown above. In contrast to most anthranilate-synthase I (ASI) homologues, this enzyme is not inhibited by tryptophan. In Streptomyces globisporus, the sequential action of this enzyme and EC 22.214.171.124, 2-amino-4-deoxychorismate dehydrogenase, leads to the formation of the benzoxazolinate moiety of the enediyne antitumour antibiotic C-1027 [1,2]. In certain Pseudomonads the enzyme participates in the biosynthesis of phenazine, a precursor for several compounds with antibiotic activity [3,4].