5-(carboxyamino)imidazole ribonucleotide synthase

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In enzymology, a 5-(carboxyamino)imidazole ribonucleotide synthase (EC 6.3.4.18) is an enzyme that catalyzes the chemical reaction

ATP + 5-amino-1-(5-phospho-D-ribosyl)imidazole + HCO₃- $\rightleftharpoons$ ADP + phosphate + 5-carboxyamino-1-(5-phospho-D-ribosyl)imidazole

The 3 substrates of this enzyme are ATP, 5-amino-1-(5-phospho-D-ribosyl)imidazole, and HCO3-, whereas its 3 products are ADP, phosphate, and 5-carboxyamino-1-(5-phospho-D-ribosyl)imidazole.

This enzyme belongs to the family of ligases, specifically those forming generic carbon-nitrogen bonds. The systematic name of this enzyme class is 5-amino-1-(5-phospho-D-ribosyl)imidazole:carbon-dioxide ligase (ADP-forming). Other names in common use include N5-CAIR synthetase, N5-carboxyaminoimidazole ribonucleotide synthetase, and PurK.

[edit] References

IUBMB entry for 6.3.4.18
BRENDA references for 6.3.4.18 (Recommended.)
PubMed references for 6.3.4.18
PubMed Central references for 6.3.4.18
Google Scholar references for 6.3.4.18
Meyer E, Leonard NJ, Bhat B, Stubbe J, Smith JM (1992). "Purification and characterization of the purE, purK, and purC gene products: identification of a previously unrecognized energy requirement in the purine biosynthetic pathway". Biochemistry. 31: 5022–32. PMID 1534690.
Mueller EJ, Meyer E, Rudolph J, Davisson VJ, Stubbe J (1994). "N5-carboxyaminoimidazole ribonucleotide: evidence for a new intermediate and two new enzymatic activities in the de novo purine biosynthetic pathway of Escherichia coli". Biochemistry. 33: 2269–78. PMID 8117684.
Thoden JB, Kappock TJ, Stubbe J, Holden HM (1999). "Three-dimensional structure of N5-carboxyaminoimidazole ribonucleotide synthetase: a member of the ATP grasp protein superfamily". Biochemistry. 38: 15480–92. PMID 10569930.