ⓘ Carbamoyl phosphate synthase II

                                     

ⓘ Carbamoyl phosphate synthase II

Carbamoyl phosphate synthetase II is an enzyme that catalyzes the reactions that produce carbamoyl phosphate in the cytosol. Its systemic name is hydrogen-carbonate:L-glutamine amido-ligase.

In the biosynthesis of pyrimidines, it is the limiting enzyme and catalyzes the following reaction:

2 ATP + L-glutamine + HCO 3 − + H 2 O ⇌ {\displaystyle \rightleftharpoons } 2 ADP + phosphate + L-glutamate + carbamoyl phosphate overall reaction 1a L-glutamine + H 2 O ⇌ {\displaystyle \rightleftharpoons } L-glutamate + NH 3 1b 2 ATP + HCO 3 − + NH 3 ⇌ {\displaystyle \rightleftharpoons } 2 ADP + phosphate + carbamoyl phosphate

It is activated by ATP and PRPP and it is inhibited by UMP Uridine monophosphate, the final product of pyrimidine synthesis path.

No CIGS or CPSII require Biotin as a coenzyme, as can be seen from most of carboxylation reactions.

This is one of three enzyme functions encoded by the gene CAD. It is classified under EC 6.3.5.5.