Phosphoribosylaminoimidazolesuccinocarboxamide synthase

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In enzymology, a phosphoribosylaminoimidazolesuccinocarboxamide synthase (EC is an enzyme that catalyzes the chemical reaction

ATP + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate + L-aspartate ADP + phosphate + (S)-2-[5-amino-1-(5-phospho-D-ribosyl)imidazole-4- carboxamido]succinate

The 3 substrates of this enzyme are ATP, 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate, and L-aspartate, whereas its 4 products are ADP, phosphate, [[(S)-2-[5-amino-1-(5-phospho-D-ribosyl)imidazole-4-]], and [[carboxamido]succinate]].

This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D-amino-acid ligases (peptide synthases). The systematic name of this enzyme class is 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate:L-aspartate ligase (ADP-forming). Other names in common use include phosphoribosylaminoimidazole-succinocarboxamide synthetase, PurC, SAICAR synthetase, 4-(N-succinocarboxamide)-5-aminoimidazole synthetase, 4-[(N-succinylamino)carbonyl]-5-aminoimidazole ribonucleotide, synthetase, SAICARs, phosphoribosylaminoimidazolesuccinocarboxamide synthetase, and 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide synthetase. This enzyme participates in purine metabolism.

Structural studies

As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes 1A48, 1KUT, 1OBD, 1OBG, 2CNQ, 2CNU, 2CNV, 2GQR, 2GQS, and 2H31.


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  • LUKENS LN, BUCHANAN JM (1959). "Biosynthesis of the purines. XXIV. The enzymatic synthesis of 5-amino-1-ribosyl-4-imidazolecarboxylic acid 5'-phosphate from 5-amino-1-ribosylimidazole 5'-phosphate and carbon dioxide". J. Biol. Chem. 234: 1799&ndash, 805. PMID 13672967.
  • Parker J (1984). "Identification of the purC gene product of Escherichia coli". J. Bacteriol. 157: 712&ndash, 7. PMID 6365889.
  • Ebbole DJ, Zalkin H (1987). "Cloning and characterization of a 12-gene cluster from Bacillus subtilis encoding nine enzymes for de novo purine nucleotide synthesis". J. Biol. Chem. 262: 8274&ndash, 87. PMID 3036807.
  • Chen ZD, Dixon JE, Zalkin H (1990). "Cloning of a chicken liver cDNA encoding 5-aminoimidazole ribonucleotide carboxylase and 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide synthetase by functional complementation of Escherichia coli pur mutants". Proc. Natl. Acad. Sci. U. S. A. 87: 3097&ndash, 101. PMID 1691501.
  • O'Donnell AF, Tiong S, Nash D, Clark DV (2000). "The Drosophila melanogaster ade5 gene encodes a bifunctional enzyme for two steps in the de novo purine synthesis pathway". Genetics. 154: 1239&ndash, 53. PMID 10757766.
  • Nelson SW, Binkowski DJ, Honzatko RB, Fromm HJ (2005). "Mechanism of action of Escherichia coli phosphoribosylaminoimidazolesuccinocarboxamide synthetase". Biochemistry. 44: 766&ndash, 74. PMID 15641804.

External links

The CAS registry number for this enzyme class is 9023-67-0.

Gene Ontology (GO) codes