chorismate + L-glutamine = anthranilate + H(+) + L-glutamate + pyruvate Amino-acid biosynthesis; L-tryptophan biosynthesis; L-tryptophan from chorismate: step 1/5. Tetramer of two components I and two components II. Component I catalyzes the formation of anthranilate using ammonia rather than glutamine, whereas component II provides glutamine amidotransferase activity.