Carbamoyl phosphate synthetase
From Proteopedia
Contents |
Function
Carbamoyl phosphate synthetase (CPS) catalyzes the production of carbamoyl phosphate from ATP, Mg+2, bicarbonate andglutamine. CPS is part of the pyrimidine and arginine biosynthesis as well as the urea cycle in vertebrates. Ornithine is an allosteric effector of CPS. There are 3 forms of CPS:
- CPS I participates in the urea cycle. CPS I uses glutamine for NH3 source.
- CPS II participates in pyrimidine metabolism
- CPS III is found in fish.
Disease
CPS I deficiency causes the accumulation of NH3 in the blood.
Structural highlights
CPS I and II are composed of 2 subunits. The large subunit contain active sites which bind nucleotides and other effectors. The small subunit catalyzes the hydrolysis of glutamine to glutamate and NH3. The small subunit active site contains an active Cys residue. CPS I contains a methylglyoxal synthetase (MGS) domain which binds ornithine.
3D structures of carbamoyl phosphate synthetase
Updated on 17-November-2015
2yvq – CPS I MGS domain - human
1jdb - EcCPS + phosphate + glutamine + ADP – Escherichia coli
1a9x, 1cs0 - EcCPS + phosphate + ornithine + ADP
1c30, 1m6v - EcCPS (mutant) + phosphate + ornithine + ADP
1bxr - EcCPS + ornithine + AMPPNP
1ce8 - EcCPS + phosphate + ornithine + inosinic acid + ADP
1c3o - EcCPS (mutant) + phosphate + ornithine + glutamine + ADP
1kee - EcCPS + phosphate + ornithine + acivicin + ADP
1t36 - EcCPS (mutant) + phosphate + ornithine + UMP + ADP
