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Information on EC 6.3.4.16 - carbamoyl-phosphate synthase (ammonia)

for references in articles please use BRENDA:EC6.3.4.16

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IUBMB Comments

The enzyme catalyses the first committed step in the urea cycle. The reaction proceeds via three separate chemical reactions: phosphorylation of hydrogencarbonate to carboxyphosphate; a nucleophilic attack of ammonia on carboxyphosphate yielding carbamate; and the phosphorylation of carbamate forming carbamoyl phosphate. Two moles of ATP are utilized for the synthesis of one molecule of carbamyl phosphate, making the reaction essentially irreversible. The enzyme requires the allosteric activator N-acetyl-L-glutamate. cf. EC 6.3.5.5, carbamoyl-phosphate synthase (glutamine-hydrolysing).

The expected taxonomic range for this enzyme is: Eukaryota, Bacteria, Archaea
Reaction Schemes
hide(Overall reactions are displayed. Show all >>)
2
ATP
+
NH3
+
hydrogencarbonate
=
2
ADP
+
phosphate
+
carbamoyl phosphate
2
+
+
=
2
+
+

Synonyms
carbamoyl phosphate synthetase, cpsase, carbamoyl-phosphate synthetase, carbamoylphosphate synthetase, cps i, cps-i, carbamyl phosphate synthetase i, cps-1, carbamoylphosphate synthase, carbamoyl phosphate synthetase i, more

REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
2 ATP + NH3 + hydrogencarbonate = 2 ADP + phosphate + carbamoyl phosphate
show the reaction diagram
ATP + carbamate = ADP + carbamoyl phosphate
show the reaction diagram
(1c)
-
-
-
ATP + hydrogencarbonate = ADP + carboxyphosphate
show the reaction diagram
(1a)
-
-
-
NH3 + carboxyphosphate = carbamate + phosphate
show the reaction diagram
(1b)
-
-
-