Carbamoyl phosphate synthase II

Carbamoyl phosphate synthetase (glutamine-hydrolysing) is an enzyme that catalyzes the reactions that produce carbamoyl phosphate in the cytosol (as opposed to type I, which functions in the mitochondria). Its systemic name is hydrogen-carbonate:L-glutamine amido-ligase (ADP-forming, carbamate-phosphorylating).

In pyrimidine biosynthesis, it serves as the rate-limiting enzyme and catalyzes the following reaction:
 * 2 ATP + L-glutamine + HCO3− + H2O $$\rightleftharpoons$$ 2 ADP + phosphate + L-glutamate + carbamoyl phosphate (overall reaction)
 * (1a) L-glutamine + H2O $$\rightleftharpoons$$ L-glutamate + NH3
 * (1b) 2 ATP + HCO3− + NH3 $$\rightleftharpoons$$ 2 ADP + phosphate + carbamoyl phosphate

It is activated by ATP and PRPP and it is inhibited by UTP (Uridine triphosphate) Neither CPSI nor CPSII require biotin as a coenzyme, as seen with most carboxylation reactions.

It is one of the four functional enzymatic domains coded by the CAD gene. It is classified under.