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CATH Superfamily 3.50.30.20

Carbamoyl-phosphate synthase small subunit, N-terminal domain

The name of this superfamily has been modified since the most recent official CATH+ release (v4_4_0). At the point of the last release, this superfamily was named:

"
Carbamoyl-phosphate synthase small subunit, N-terminal domain
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 2: Carbamoyl-phosphate synthase 1, mitochondrial

There are 4 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Carbamoyl-phosphate synthase (glutamine-hydrolyzing). [EC: 6.3.5.5]
2 ATP + L-glutamine + HCO(3)(-) + H(2)O = 2 ADP + phosphate + L-glutamate + carbamoyl phosphate.
  • The product carbamoyl phosphate is an intermediate in the biosynthesis of arginine and the pyrimidine nucleotides.
  • The enzyme from Escherichia coli has three separate active sites, which are connected by a molecular tunnel that is almost 100 A in length.
  • The amidotransferase domain within the small subunit of the enzyme hydrolyzes glutamine to ammonia via a thioester intermediate.
  • The ammonia migrates through the interior of the protein, where it reacts with carboxyphosphate to produce the carbamate intermediate.
  • The carboxyphosphate intermediate is formed by the phosphorylation of hydrogencarbonate by ATP at a site contained within the N-terminal half of the large subunit.
  • The carbamate intermediate is transported through the interior of the protein to a second site within the C-terminal half of the large subunit, where it is phosphorylated by another ATP to yield the final product, carbamoyl phosphate.
  • Cf. EC 6.3.4.16.
  • Formerly EC 2.7.2.9.
 7 B2RQC6 O93937 P07259 P08955 P27708 Q09794 Q91437
Aspartate carbamoyltransferase. [EC: 2.1.3.2]
Carbamoyl phosphate + L-aspartate = phosphate + N-carbamoyl-L-aspartate.
    		 7 B2RQC6 O93937 P07259 P08955 P27708 Q09794 Q91437
    Carbamoyl-phosphate synthase (ammonia). [EC: 6.3.4.16]
    2 ATP + NH(3) + HCO(3)(-) = 2 ADP + phosphate + carbamoyl phosphate.
    • The enzyme catalyzes 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.
    • Formerly EC 2.7.2.5.
    		 6 A0A024R454 A0A024R454 P07756 P31327 P31327 Q8C196
    Dihydroorotase. [EC: 3.5.2.3]
    (S)-dihydroorotate + H(2)O = N-carbamoyl-L-aspartate.
      		 4 B2RQC6 P08955 P27708 Q91437
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