Hydroxyl Radical Generation by Mammalian Catalase: A Few Experimental Evidences

Madhur M Goyal, Ajay Meshra

Abstract

Catalase is well known antioxidant enzyme which protects cells from the toxic effects of hydrogen peroxide. Unlike peroxidase, it catalyses the dissociation of hydrogen peroxide directly into H2O and O2. Our results show that apart from the known catalytic action, mammalian catalase can generate Hydroxyl Radicals (HRs) in experimental conditions. At low concentrations of H2O2 (<20 μM), the presence of bovine liver catalase (BLC) increased the generation of HRs in the reaction mixture. Differential productions of HRs due to either presence of azide or urea induced structural changes of BLC suggest that the enzyme participates in the production of HRs. The possible character is unusual in contrast to the well-established fact that catalase reduce the generation of reactive oxygen species in a biological system. The work is being presented with a discussion on experimental limitations we faced throughout the study.\r\n