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).^{[1][2][3][4][5][6][7][8]}

Carbamoyl-phosphate synthetase (glutamine-hydrolysing)
Identifiers
EC no.	6.3.5.5
CAS no.	37233-48-0
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

carbamoyl-phosphate synthetase 1, aspartate transcarbamylase, and dihydroorotase
Identifiers
Symbol	CAD
NCBI gene	790
HGNC	1424
OMIM	114010
RefSeq	NM_004341
UniProt	P27708
Other data
Locus	Chr. 2 p21
Search for Structures Swiss-model Domains InterPro

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^[9] and it is inhibited by UTP (Uridine triphosphate)^[10] 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.^[11] The CAD gene is a large gene. It uses a single strand to code for these enzyme jobs. It is classified under EC 6.3.5.5.

See also

• Carbamoyl phosphate synthetase I
• Carbamoyl phosphate synthetase III