The kinetic mechanism of glutathione peroxidase from human platelets

Human platelet glutathione peroxidase (GSH-Px) exhibits a ping-pong type kinetic mechanism. Peroxide changes the redox state of the enzyme and renders it highly stable against attack by alkylating agents. Peroxide seems also to act as a positive homotropic modulator modifying the allosteric kinetics of the enzyme. The combination of these two mechanisms accelerates response against peroxides. This finding reassesses importance of GSH-Px for the platelet protection.