PF1661 hisH IGP synthase glutamine amidotransferase subunit 194 IGP synthase subunit HisH ImGP synthase subunit HisH MDRIAIVDLGIGNLANVKKALKGYITSDPYEIEKADKIVLPGVGNFGAVVDKLAPIKDIIIEGINEGKPFLGICLGMQLLFEESEESPGKEGLGIFKGKVVKLKNVRTPHIGWNQVWIKKECKLFEGLKNGSYFYFVHSYHAVPQDPDIIATTTDYENAEFVSSVCFENIFGVQFHPEKSSKNGLILLRNFRRL HIS5_PYRFU Imidazole glycerol phosphate synthase subunit HisH IGPS catalyzes the conversion of PRFAR and glutamine to IGP, AICAR and glutamate. The HisH subunit provides the glutamine amidotransferase activity that produces the ammonia necessary to HisF for the synthesis of IGP and AICAR (By similarity).