Kinetic model of imidazologlycerol-phosphate synthetase from Escherichia coli

Oleg V. Demin, Igor Goryanin, S. Dronov, Galina Lebedeva

Research output: Contribution to journalArticlepeer-review

Abstract

Based on the available experimental data, we developed a kinetic model of the catalytic cycle of imidazologlycerol-phosphate synthetase from Escherichia coli accounting for the synthetase and glutaminase activities of the enzyme. The rate equations describing synthetase and glutaminase activities of imidazologlycerol-phosphate synthetase were derived from this catalytic cycle. Using the literature data, we evaluated all kinetic parameters of the rate equations characterizing individually synthetase and glutaminase activities as well as the contribution of each activity depending on concentration of the substrates, products, and effectors. As shown, in the presence of 5′-phosphoribosylformimino-5-aminoimidazolo-4-carboxamideribonucleotide (ProFAR) and imidazologlycerol phosphate (IGP) glutaminase activity dominates over synthetase activity at sufficiently low concentrations of 5′-phosphoribulosylformimino-5-aminoimidazolo-4-carboxamideribonucleotide (PRFAR). Increased PRFAR concentrations resulted in decreased contribution of glutaminase activity and, consequently, increased the contribution of synthetase activity in the enzyme functioning.
Original languageEnglish
Pages (from-to)1324-1335
Number of pages12
JournalBiochemistry
Volume69
Issue number12
DOIs
Publication statusPublished - 2004

Keywords

  • imidazologlycerol-phosphate synthetase
  • catalytic cycle
  • model

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