title: Site specific modification of the human plasma proteome by methylglyoxal.
abstract: Increasing evidence identifies dicarbonyl stress from reactive glucose metabolites, such as methylglyoxal (MG), as a major pathogenic link between hyperglycemia and complications of diabetes. MG covalently modifies arginine residues, yet the site specificity of this modification has not been thoroughly investigated. Sites of MG adduction in the plasma proteome were identified using LC-MS/MS analysis in vitro following incubation of plasma proteins with MG. Treatment of plasma proteins with MG yielded 14 putative MG hotspots from five plasma proteins (albumin [nine hotspots], serotransferrin, haptoglobin [2 hotspots], hemopexin, and Ig lambda-2 chain C regions). The search results revealed two versions of MG-arginine modification, dihydroxyimidazolidine (R+72) and hydroimidazolone (R+54) adducts. One of the sites identified was R257 in human serum albumin, which is a critical residue located in drug binding site I. This site was validated as a target for MG modification by a fluorescent probe displacement assay, which revealed significant drug dissociation at 300 μM MG from a prodan-HSA complex (75 μM). Moreover, twelve human plasma samples (six male, six female, with two type 2 diabetic subjects from both genders) were analyzed using multiple reaction monitoring (MRM) tandem mass spectrometry and revealed the presence of the MG-modified albumin R257 peptide. These data provide insights into the nature of the site-specificity of MG modification of arginine, which may be useful for therapeutic treatments that aim to prevent MG-mediated adverse responses in patients.
authors.affiliation: Southwest Environmental Health Sciences Center, Department of Pharmacology & Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kimzey
authors.affiliation: Southwest Environmental Health Sciences Center, Department of Pharmacology & Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: Owen R
authors.initials: OR
authors.lastname: Kinsky
authors.affiliation: Department of Medicine, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: Hussein N
authors.initials: HN
authors.lastname: Yassine
authors.affiliation: Southwest Environmental Health Sciences Center, Department of Pharmacology & Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: George
authors.initials: G
authors.lastname: Tsaprailis
authors.affiliation: Department of Medicine, The University of Arizona, Tucson, AZ 85721, United States; Southern Arizona VA Health Care System, Tucson, AZ 85723, United States.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Stump
authors.affiliation: Southwest Environmental Health Sciences Center, Department of Pharmacology & Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: Terrence J
authors.initials: TJ
authors.lastname: Monks
authors.affiliation: Southwest Environmental Health Sciences Center, Department of Pharmacology & Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States. Electronic address: lau@pharmacy.arizona.edu.
authors.forename: Serrine S
authors.initials: SS
authors.lastname: Lau
mesh_terms: D001120:Arginine; D001665:Binding Sites; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis; D005260:Female; D057166:High-Throughput Screening Assays; D006801:Humans; D008297:Male; D010449:Peptide Mapping; D011485:Protein Binding; D050050:Protein Carbonylation; D011499:Protein Processing, Post-Translational; D040901:Proteomics / Q000379:methods; D011765:Pyruvaldehyde / Q000097:blood*; D012709:Serum Albumin / Q000378:metabolism; D000075462:Serum Albumin, Human; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: C422455:ALB protein, human; D015415:Biomarkers; D001798:Blood Proteins; D012709:Serum Albumin; D011765:Pyruvaldehyde; D001120:Arginine; D000075462:Serum Albumin, Human
keywords: Adducts; Glyco-oxidation; Methylglyoxal; Proteomics; Type 2 diabetes mellitus