Effect of Hydrogen Peroxide and Catalase Derivatives on Functional Activity of Platelets

Effects of H₂O₂ on platelet aggregation were estimated in vitro in the presence and absence of inductors (ADP, serotonin, TRAP) and native and modified catalase. Dose-dependent effect of H₂O₂ (50 μM or more) was investigated in a pathophysiological concentration of 300 μM inducing platelet aggregation. H₂O₂ modulated aggregation induced by ADP, serotonin, and TRAP significantly increasing the initial platelet aggregation followed by disaggregation, which was always more pronounced than in control. Catalase derivatives (native and modified forms) dose-dependently reduced the effect of H₂O₂ and completely abolished it in a dose of 9000 U catalase activity per 1 ml of solution for native catalase and 1200 U/ml for modified one. Modified catalase, in contrast to native one, produced an independent inhibitory effect on induced platelet aggregation. Components of modified catalase (individual substance and simple mixture) had no antiaggregant effect.