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
2.4.2.18 (anthranilate phosphoribosyltransferase), EC
4.1.3.27 (anthranilate synthase), EC
4.2.1.20 (tryptophan synthase) and EC
5.3.1.24 (phosphoribosylanthranilate isomerase)].