[Catalytic properties of catalase in microemulsions of surface-active agents in octane].
The rate constants of H2O2 decomposition, interaction of catalase complex I with H2O2, and the effective rate constants of catalase inactivation during enzymatic catalysis (k(in)) were determined by transformation of complete kinetic curves of H2O2 decomposition by catalase in reversed micelles of Aerosol OT (AOT) in octane and aqueous solution. Effects of hydration of micelles and AOT, H2O2, and catalase concentrations in the micellar systems on each of three kinetic constants were investigated. Optimal conditions were found which provide for high operational stability and catalytic activity of catalase in micellar systems versus aqueous solutions. Stability of catalase enhances (decreased k(in)) in the presence of reduced glutathione and ethanol in AOT micelles. In reversed AOT micelles, catalase partially dissociates to subunits because their peroxidase activity was demonstrable in cumene hydroperoxide-dependent oxidation of tetramethylbenzidine. Catalase dissociation to monomers is significantly decreased in mixed micelles composed of AOT, Triton X-45, Triton X-100, or Tween-85 and octanol.
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D002374:Catalase / Q000378:metabolism*; D002384:Catalysis; D004143:Dioctyl Sulfosuccinic Acid; D004655:Emulsions; D004795:Enzyme Stability; D007700:Kinetics; D008823:Micelles; D013501:Surface-Active Agents
D004655:Emulsions; D008823:Micelles; D013501:Surface-Active Agents; D004143:Dioctyl Sulfosuccinic Acid; D002374:Catalase