In some organisms, this enzyme is part of a multifunctional protein, together with one or more other components of the system for the biosynthesis of tryptophan [EC 188.8.131.52 (anthranilate phosphoribosyltransferase ), EC 184.108.40.206 (indole-3-glycerol-phosphate synthase), EC 220.127.116.11 (tryptophan synthase) and EC 18.104.22.168 (phosphoribosylanthranilate isomerase)]. The native enzyme in the complex uses either glutamine or, less efficiently, NH3. The enzyme separated from the complex uses NH3 only.
wild-type and 2 classes of mutants: one is defective in the chorismate-binding subunit E and is incapable of catalyzing the anthranilate synthetase reaction. The second class is defective in the G subunit but produces an active E subunit, this mutation results in a requirement for p-aminobenzoate in addition to anthranilate
one anthranilate synthase participates in Trp synthesis and is encoded by the genes trpE and trpG, the other anthranilate synthase is encoded by the genes phnA and phnB and participates in the synthesis of pyocyanin