[Changes in the antioxidant properties of substituted phenol polydisulfides during interaction with human serum albumin].
Gallic acid polydisulfide and poly(2-aminodisulfide-4-nitrophenol) in aqueous solutions were shown to form polycomplexes with human serum albumin. This process was accompanied by considerable changes in the spectrum of protein circular dichroism recorded in distilled water in the far UV range at 20 degrees C. Complex formation between human serum albumin and polydisulfides was followed by a marked decrease in the content of alpha-helices and increase in the count of antiparallel beta-structures in the protein. Stable complexes containing 1.5, 2.8, and 7.7 poly(2-aminodisulfide-4-nitrophenol) molecules per human serum albumin molecule were formed in bicarbonate buffer (pH 9.0). In these complexes, the secondary protein structure underwent changes similar to those in polycomplexes of human serum albumin and polydisulfides. Gallic acid polydisulfide and poly(2-aminodisulfide-4-nitrophenol) inhibited the catalase-induced degradation of 50 mM H2O2. Complexes of human serum albumin and poly(2-aminodisulfide-4-nitrophenol) increased the catalytic activity and operational stability of catalase 1.5 and 4-7-fold, respectively. This was characterized by the effective reaction rate constant (kin, s-1). Our results indicate that complexes of human serum albumin and substituted phenol polydisulfides act as potent protectors and activators of catalase during enzymatic degradation of H2O2 at high concentrations.
Metelitsa
D I
DI
Institute of Bioorganic Chemistry, Academy of Sciences of Belarus, Minsk, 220141 Belarus.
Eremin
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AN
D000818:Animals; D000975:Antioxidants / Q000737:chemistry*; D002374:Catalase / Q000737:chemistry; D002417:Cattle; D002942:Circular Dichroism; D004220:Disulfides / Q000737:chemistry*; D004795:Enzyme Stability; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D009596:Nitrophenols / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012709:Serum Albumin / Q000737:chemistry*
D000975:Antioxidants; D004220:Disulfides; D009596:Nitrophenols; D012709:Serum Albumin; D006861:Hydrogen Peroxide; D002374:Catalase
Izmeneniia antioksidantnykh svoĭsv polidisul'fidov zameshchennykh fenolov pri ikh vzaimodeĭstvii s syvorotochnym al'buminom cheloveka.