carbamoyl-phosphate synthase (ammonia) activity

Definition

Target type: molecularfunction

Catalysis of the reaction: 2 ATP + hydrogencarbonate + NH4+ = 2 ADP + carbamoyl phosphate + 2 H+ + phosphate. [EC:6.3.4.16, RHEA:18029]

Carbamoyl-phosphate synthase (ammonia) activity catalyzes the biosynthesis of carbamoyl phosphate, a key intermediate in the synthesis of both pyrimidines and arginine. This reaction involves the condensation of ammonia, carbon dioxide, and ATP. The enzyme utilizes two molecules of ATP, one for the activation of bicarbonate to form carboxyphosphate and the other for the phosphorylation of ammonia to form carbamoyl phosphate. The overall reaction can be described as:

2 ATP + HCO3- + NH3 → 2 ADP + Pi + H2O + carbamoyl phosphate

The active site of carbamoyl-phosphate synthase (ammonia) is comprised of three distinct domains: the carbamate domain, the phosphate domain, and the glutamine amidotransferase domain. The carbamate domain binds bicarbonate and ATP, while the phosphate domain binds ATP and catalyzes the phosphorylation of ammonia. The glutamine amidotransferase domain is responsible for the transfer of ammonia from glutamine to the active site, which is essential for the overall reaction.

Carbamoyl-phosphate synthase (ammonia) is a highly regulated enzyme, with its activity being influenced by various factors, including the availability of substrates, the levels of allosteric regulators, and the cellular environment. The enzyme plays a critical role in the metabolism of nitrogen and is essential for the synthesis of pyrimidines, arginine, and other biomolecules.'
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Proteins (1)

Compounds (1)