- Source: Carbamoyl phosphate synthase II
Carbamoyl phosphate synthetase (glutamine-hydrolysing) (EC 6.3.5.5) 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
⇌
{\displaystyle \rightleftharpoons }
2 ADP + phosphate + L-glutamate + carbamoyl phosphate (overall reaction)
(1a) L-glutamine + H2O
⇌
{\displaystyle \rightleftharpoons }
L-glutamate + NH3
(1b) 2 ATP + HCO3− + NH3
⇌
{\displaystyle \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 EC 6.3.5.5.
See also
Carbamoyl phosphate synthetase I
Carbamoyl phosphate synthetase III
References
External links
Carbamoyl-Phosphate+Synthase+(Glutamine-Hydrolyzing) at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Kata Kunci Pencarian:
- Carbamoyl phosphate synthase II
- Carbamoyl phosphate synthetase
- CPS
- CPS II
- Urea cycle
- Mitochondrial matrix
- CPS2
- Transferase
- List of EC numbers (EC 2)
- Mitomycins
