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Abstract

Specific features of metal-catalyzed oxidation (MCO) of purified proteins (human serum albumin and human erythrocyte superoxide dismutase) were analyzed by the oxidation level of tryptophan and tyrosine. The production of dityrosine cross-links and the oxidation of tryptophan residues were recorded by fluorescence. The degree of oxidative modification of the amino acid residues of the proteins depended on the concentration of the Fenton's medium components and on the incubation time. These changes were different in different proteins. By electrophoresis and gel-permeation chromatography, changes in the superoxide dismutase structure are shown to be caused by oxidative modification of the enzyme and to be accompanied by a decrease in its activity. Findings with OH* scavengers (mannitol and ethanol) suggest that oxidative modification of the proteins in Fenton's medium should be associated not only with hydroxyl radical but also with ferryl and perferryl ions and with the radical CO(-.)(3).

Phosphorylation and Carbonylation of Placental Proteins in Normal Pregnancy and Gestosis

“…Free radicals, for example, hydroxyl radical and superoxide anion radical, can destroy not only lateral chains of amino acid residues, but can also oxidize the protein molecule skeleton in the α-carbon atom region and hence, modify its function [2]. The detected modification of placental protein phosphorylation can also significantly modulate the biochemical mechanisms of cell regulation.…”

Role of Cu2+ in Free Radical Oxidation of Human Serum Albumin and L-Tyrosine Dipeptide with Multicomponent Metal-Containing Xenobiotic

“…Fluorescence of dityrosine was measured at the excitation and emission wavelengths of 325 and 16 nm, respectively. Fluorescence of tryptophan was measured at excitation and emission wavelengths of 297 and 336 nm, respectively [2].…”

“…Oxidation of tryptophan (a) and tyrosine residues (b) of human serum albumin as a function of concentrations of CuSO 4 (1) and copper-containing solution(2). Here and inFig.…”

“…Dityrosine formation in the solution of dipeptide tyrosine at different concentrations of CuSO 4 (1) and copper-containing solution(2).…”

Evaluation of the resistance of blood plasma to oxidative stress by oxidizability of proteins and lipids during metal-catalyzed oxidation

“…In light of this, valuable information can be obtained in the analysis of potential vulnerability of plasma lipids to Cu 2+ -catalyzed oxidation in vitro (oxidizability or oxidative resistance). Under these conditions, oxidation occurs at high dilution, depends little on the influence of water-soluble plasma antioxidants, and is mainly affected by fat-soluble compounds [1].…”