title: Biochemical and spectrophotometric significance of advanced oxidized protein products.
abstract: We previously described the presence of advanced oxidation protein products (AOPP), a novel marker of oxidative stress in the plasma of hemodialyzed patients (HD). The present study was carried out to further investigate how myeloperoxidase (MPO)-catalyzed reactions could contribute to AOPP generation in the plasma. First, patterns of plasma protein oxidation obtained after in vitro incubation of control plasma with hypochlorous acid (HOCl) were compared to those from HD patients and control plasma. The use of various analytical techniques enabled localising and identifying the main oxidized proteins with albumin (HSA) after protein separation by size-exclusion chromatography and SDS-PAGE electrophoresis. The characterization of the oxidation level of the individual plasma proteins in terms of carbonyl groups and 3-nitrotyrosine formations was performed by immunoblotting. Secondly, to highlight the significance of AOPP index monitored by spectrophotometry, spectra were established for plasma fractions from HD patients and compared to data for control plasma and HOCl-treated plasma. The corresponding absorbance difference spectra were matched with external standards such as dityrosine, nitrotyrosine and pentosidine and elaborated chromophoric probe models. Indeed, HSA was chlorinated by HOCl reagent or HOCl generated via the MPO/H(2)O(2)/Cl(-) system and was nitrated by tetranitromethane. Increased absorbances at the range of 340 nm were observed both with chlorinated and nitrated HSA. Finally, our results indicate that HOCl, and not NO(2)(*), generated via MPO activity, could represent one of the pathways for AOPP production in plasma proteins exposed to activated phagocytes.
authors.affiliation: Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (CNRS UMR 8601) Université Paris 5, Faculty of Medicine, 45 rue des Saints Pères, 75270 Paris Cedex 06, France. Chantal.Capeillere-Blandin@univ-paris5.fr
authors.forename: Chantal
authors.initials: C
authors.lastname: Capeillère-Blandin
authors.forename: Valérie
authors.initials: V
authors.lastname: Gausson
authors.forename: Béatrice
authors.initials: B
authors.lastname: Descamps-Latscha
authors.forename: Véronique
authors.initials: V
authors.lastname: Witko-Sarsat
mesh_terms: D015415:Biomarkers / Q000097:blood*; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006997:Hypochlorous Acid / Q000737:chemistry; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D009195:Peroxidase / Q000097:blood / Q000378:metabolism*; D006435:Renal Dialysis / Q000379:methods*; D051437:Renal Insufficiency / Q000097:blood / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism; D013053:Spectrophotometry / Q000379:methods*
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D009573:Nitrites; D012709:Serum Albumin; D006997:Hypochlorous Acid; D009195:Peroxidase