Carbamoyl phosphate is a biologically important anion. In terrestrial animals, carbamoyl phosphate serves as a metabolic intermediate in both nitrogen disposal through the urea cycle and pyrimidine synthesis. Its enzymatic counterpart, carbamoyl phosphate synthetase I (CPS I), interacts with a class of molecules called sirtuins, NAD dependent protein deacetylases, and ATP to form carbamoyl phosphate. CP then enters the urea cycle in which it reacts with ornithine (a process catalyzed by the enzyme ornithine transcarbamylase) to form citrulline.
Classification Carbamoyl phosphate is a metabolic intermediate in a pathway that involves nitrogen disposal through the urea cycle and the biosynthesis of pyrimidines.
Production It is produced from bicarbonate, ammonia (derived from amino acids), and phosphate (from ATP). The synthesis is catalyzed by the enzyme carbamoyl phosphate synthetase. This uses three reactions as follows:
+ ATP → ADP + () + NH3 + OH− → + −O–C(O)NH2 + H2O −O–C(O)NH2 + ATP → ADP +
Clinical significance A defect in the CPS I enzyme, and a subsequent deficiency in the production of carbamoyl phosphate has been linked to hyperammonemia in humans.
See also Ornithine transcarbamylase Citrulline Mary Ellen Jones (chemist) Urea Cycle
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