1. A multifunctional protein (2225 aa) with the enzymatic activities required for the first three steps of the de novo pyrimidine synthesis pathway: glutamine-dependent carbamoyl-phosphate synthase (EC 188.8.131.52), aspartate carbamoyltransferase (EC 184.108.40.206), and dihydro-orotase (EC 220.127.116.11). It is allosterically regulated and loses feedback inhibition when phosphorylated.
2. See DNA fragmentation factor.