Influence of hydration degree of aerosol OT reversed micelles in heptane on inhibitory effect of gallic acid polydisulfide in peroxidase-dependent oxidation of 3,3;,5,5;-tetramethylbenzidine.
Gallic acid polydisulfide (GAPD) inhibits with high efficiency tetramethylbenzidine (TMB) peroxidation at 20 degreesC in reversed aerosol OT (AOT) micelles in heptane with various hydration degrees w0 ranging from 8.3 to 47.2. Like in aqueous medium, the inhibition constant Ki for GAPD is approximately 10(-6) M and decreases with increasing w0 from 15.3 to 25. In AOT micelles with various hydration degree, the initial rates of TMB oxidation catalyzed by peroxidase were determined in the absence of GAPD (v0). Using the dependencies of the induction time of TMB peroxidation on the initial GAPD concentration, the values of the stoichiometric coefficient for inhibition by GAPD (f) were calculated at various hydration degrees of AOT micelles. Increase of hydration degree of AOT micelles is accompanied by a decrease of coefficient f from 30-31 (at low hydration degree) to 11.5-12.5 (at w0 > 30), and this significantly exceeds the f values (2) typical for most known inhibitors.
Karasyova
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Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, 220141, Belarus. ibochbel@ns.igs.ac.by
Metelitza
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D001560:Benzidines / Q000378:metabolism; D002863:Chromogenic Compounds; D004305:Dose-Response Relationship, Drug; D005707:Gallic Acid / Q000378:metabolism*; D006536:Heptanes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008823:Micelles; D009195:Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*