title: Isolation of a multifunctional protein with aminoimidazole ribonucleotide synthetase, glycinamide ribonucleotide synthetase, and glycinamide ribonucleotide transformylase activities: characterization of aminoimidazole ribonucleotide synthetase.
abstract: 5-Aminoimidazole ribonucleotide (AIR) synthetase, glycinamide ribonucleotide (GAR) synthetase, and GAR transformylase activities from chicken liver exist on a single polypeptide of Mr 110,000 [Daubner, C. S., Schrimsher, J. L., Schendel, F. J., Young, M., Henikoff, S., Patterson, D., Stubbe, J., & Benkovic, S. J. (1985) Biochemistry 24, 7059-7062]. Details of copurification of these three activities through four chromatographic steps are reported. The ratios of these activities remain constant throughout the purification. AIR synthetase has an absolute requirement for K+ for activity and under these conditions has apparent molecular weights of 330,000, determined by Sephadex G-200 chromatography, and 133,000, determined by sucrose density gradient ultracentrifugation. Incubation of 18O-labeled formylglycinamidine ribonucleotide (FGAM) with AIR synthetase results in stoichiometric production of AIR, ADP, and [18O]Pi. NMR spectra of beta-FGAM and beta-AIR are reported.
mesh_terms: D000217:Acyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D019731:Carbon-Nitrogen Ligases; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D019877:Hydroxymethyl and Formyl Transferases; D007700:Kinetics; D008025:Ligases / Q000302:isolation & purification* / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000302:isolation & purification* / Q000378:metabolism; D051026:Phosphoribosylglycinamide Formyltransferase
chemical_list: D009097:Multienzyme Complexes; D019877:Hydroxymethyl and Formyl Transferases; D051026:Phosphoribosylglycinamide Formyltransferase; D000217:Acyltransferases; D008025:Ligases; D019731:Carbon-Nitrogen Ligases; C022380:phosphoribosylaminoimidazole synthase; C022387:phosphoribosylamine-glycine ligase