Involved in the urea cycle of ureotelic animals where the enzyme plays an important role in removing excess ammonia from the cell. 2 ATP + hydrogencarbonate + NH4(+) = 2 ADP + carbamoyl phosphate + 2 H(+) + phosphate Requires N-acetyl-L-glutamate (NAG) as an allosteric activator. Activated by glycerol in the absence of NAG, whereas in the presence of NAG it is inhibited by increasing concentrations of glycerol. Can form homooligomers (monomers as predominant form and dimers). Primarily in the liver and small intestine. The type-1 glutamine amidotransferase domain is defective. Undergoes proteolytic cleavage in the C-terminal region corresponding to the loss of approximately 12 AA residues from the C-terminus. Succinylated at Lys-287 and Lys-1291. Desuccinylated at Lys-1291 by SIRT5, leading to activation (By similarity). Glutarylated. Glutarylation levels increase during fasting. Deglutarylated by SIRT5 at Lys-55, Lys-219, Lys-412, Lys-889, Lys-892, Lys-915, Lys-1360 and Lys-1486, leading to activation. The disease is caused by variants affecting the gene represented in this entry. Disease susceptibility is associated with variants affecting the gene represented in this entry. CPS1 variants influence the availability of precursors for nitric oxide (NO) synthesis and play a role in clinical situations where endogenous NO production is critically important, such as neonatal pulmonary hypertension, increased pulmonary artery pressure following surgical repair of congenital heart defects or hepatovenocclusive disease following bone marrow transplantation. Infants with neonatal pulmonary hypertension homozygous for Thr-1406 have lower L-arginine concentrations than neonates homozygous for Asn-1406 (PubMed:11407344). Extended N-terminus. Carbamoyl-Phosphate Synthetase 1 (CPS1)