[Determining role of media in peroxide oxidation of aromatic type antioxidants with participation of methemalbumins].
Participation of the complexes of hemin and albumins (or delipidated albumins) in peroxidation of aromatic free radical scavengers and antioxidants was studied at varying hemin/albumin ratios. The radical-scavenging amines included o-phenylenediamine (OPD) and tetramethylbenzidine (TMB); the antioxidants, gallic acid (GA) and GA polydisulfide (GAPD). Peroxidation reactions were carried out in buffered physiological saline (BPS) supplemented with 2% dimethylsulfoxide(DMSO), pH 7.4 (medium A), or in 40% aqueous dimethylformamide (DMF), pH 7.4 (medium B). In all systems involving methemalbumins, kinetic constants (kcat), Michaelis constants (kM), and the ratios thereof (kcat/kM) were determined for OPD oxidation in medium A and TMB oxidation in medium B. Oxidation of OPD, GA, and GAPD in medium A was characterized by a decrease in the catalytic activity of hemin after the formation of hemin-albumin complexes. Conversely, oxidation of TMB and OPD in medium B was distinguished by pronounced activation of hemin present within methemalbumins.
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Institute of Bioorganic Chemistry, National Academy of Sciences of Belorussia, Minsk.
Puchkaev
A V
AV
Metelitsa
D I
DI
D000975:Antioxidants / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D006427:Hemin / Q000737:chemistry; D007700:Kinetics; D008705:Methemalbumin / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*
D000975:Antioxidants; D016166:Free Radical Scavengers; D008705:Methemalbumin; D010545:Peroxides; D006427:Hemin