Site specific modification of the human plasma proteome by methylglyoxal

Michael J. Kimzey, Owen R. Kinsky, Hussein N. Yassine, George Tsaprailis, Craig S Stump, Terrence Monks, Serrine Lau

Research output: Contribution to journalArticle

12 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)155-162
Number of pages8
JournalToxicology and Applied Pharmacology
Volume289
Issue number2
DOIs
StatePublished - Dec 1 2015

Keywords

  • Adducts
  • Glyco-oxidation
  • Methylglyoxal
  • Proteomics
  • Type 2 diabetes mellitus

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

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