title: Proteomic analysis of arginine adducts on glyoxal-modified ribonuclease.
abstract: Accumulation of advanced glycation end-products (AGEs) on proteins is associated with the development of diabetic complications. Although the overall extent of modification of protein by AGEs is limited, localization of these modifications at a few critical sites might have a significant effect on protein structure and function. In the present study, we describe the sites of modification of RNase by glyoxal under physiological conditions. Arg39 and Arg85, which are closest to the active site of the enzyme, were identified as the primary sites of formation of the glyoxal-derived dihydroxyimidazolidine and hydroimidazolone adducts. Lower amounts of modification were detected at Arg10, while Arg33 appeared to be unmodified. We conclude that dihydroxyimidazolidine adducts are the primary products of modification of protein by glyoxal, that Arg39 and Arg85 are the primary sites of modification of RNase by glyoxal, and that modification of arginine residues during Maillard reactions of proteins is a highly selective process.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Cotham
authors.forename: Thomas O
authors.initials: TO
authors.lastname: Metz
authors.forename: P Lee
authors.initials: PL
authors.lastname: Ferguson
authors.forename: Jonathan W C
authors.initials: JW
authors.lastname: Brock
authors.forename: Davinia J S
authors.initials: DJ
authors.lastname: Hinton
authors.forename: Suzanne R
authors.initials: SR
authors.lastname: Thorpe
authors.forename: John W
authors.initials: JW
authors.lastname: Baynes
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Ames
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001120:Arginine / Q000737:chemistry*; D001665:Binding Sites; D002417:Cattle; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D004229:Dithiothreitol / Q000494:pharmacology; D006037:Glyoxal / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D012260:Ribonucleases / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors; D014357:Trypsin / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D007093:Imidazoles; D010455:Peptides; C117197:imidazolone; D006037:Glyoxal; D001120:Arginine; D012260:Ribonucleases; D014357:Trypsin; D004229:Dithiothreitol