Polydisulfides of substituted phenols as effective protectors of peroxidase against inactivation by ultrasonic cavitation.
Kinetics of inactivation of horseradish peroxidase (HP) induced by low-frequency ultrasonic (US) treatment (27 kHz) with the specific power of 60 W/cm2 were studied in phosphate (pH 7.4) and acetate (pH 5.2) buffers within the temperature range of 36.0 to 50.0 degrees C and characterized by effective first-order rate constants of US inactivation k(in)(us) in min(-1). Values of k(in)(us) depend on the specific ultrasonic power within the range of 20-60 W/cm2, on the concentration of HP, and on pH and temperature of the solutions. The activation energy of US inactivation of HP is 9.4 kcal/mole. Scavengers of HO* radicals, mannitol and dimethylformamide, significantly inhibit the US inactivation of HP at 36.0 degrees C, whereas micromolar concentrations of polydisulfide of gallic acid (poly(DSG)) and of poly(2-aminodisulfide-4-nitrophenol) (poly(ADSNP)) virtually completely suppress the US inactivation of peroxidase at the ultrasonic power of 60 W/cm2 on the sonication of the enzyme solutions for more than 1 h at pH 5.2. Various complexes of poly(DSG) with human serum albumin effectively protect HP against the US inactivation in phosphate buffer (pH 7.4). The findings unambiguously confirm a free radical mechanism of the US inactivation of HP in aqueous solutions. Polydisulfides of substituted phenols are very effective protectors of peroxidase against inactivation caused by US cavitation.
Grintsevich
E E
EE
Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, 220141, Belarus.
Adzerikho
I E
IE
Mrochek
A G
AG
Metelitza
D I
DI
D004220:Disulfides / Q000737:chemistry / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005707:Gallic Acid / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009195:Peroxidase / Q000187:drug effects* / Q000528:radiation effects*; D010636:Phenols / Q000737:chemistry; D012709:Serum Albumin / Q000494:pharmacology; D014465:Ultrasonics
D004220:Disulfides; D016166:Free Radical Scavengers; D010636:Phenols; D012709:Serum Albumin; D005707:Gallic Acid; D009195:Peroxidase