title: Reaction between protein radicals and other biomolecules.
abstract: The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2)-activated immobilized horseradish peroxidase (im-HRP). Subsequently, each of the three different biomolecules was separately added to the BSA radicals, after removal of im-HRP by centrifugation. Electron spin resonance (ESR) spectroscopy showed that all three biomolecules quenched the BSA radicals. Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid oil-in-water emulsion resulted in additional formation of lipid hydroperoxides and conjugated dienes. The results clearly show that protein radicals have to be considered as dynamic species during oxidative processes in biological systems and that protein radicals should not be considered as end-products, but rather as reactive intermediates during oxidative processes in biological systems hereby supporting recent data.
authors.affiliation: Danish Institute of Agricultural Sciences, Department of Animal Product Quality, Research Centre Foulum, Tjele, Denmark. Henrik.Ostdal@agrsci.dk
authors.forename: Henrik
authors.initials: H
authors.lastname: Østdal
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davies
authors.forename: Henrik J
authors.initials: HJ
authors.lastname: Andersen
mesh_terms: D000818:Animals; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000378:metabolism* / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013113:Spin Labels; D013229:Stearic Acids / Q000737:chemistry / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology; D014527:Uric Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D010455:Peptides; D011108:Polymers; D013113:Spin Labels; D013229:Stearic Acids; D014527:Uric Acid; D012710:Serum Albumin, Bovine; C020749:GAT; C031183:stearic acid; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase