Partial Purification and Properties of Catalase from Brassia oleracea capitata

Catalase (EC. 1.11.1.6.H2O2. oxidoreductase) has been found in all aerobic organisms. Most of the work preformed on this enzyme obtained from mammalian, bacterial and fungal sources as there is less information about plant catalases. Partial purification of catalase from Brassica oleracea capitata (Cabbage) and its kinetics was studied. To this intention, freshly harvested cabbage leaves freezed in liquid nitrogen, reduced to small pieces and blended. The extraction with 0.1 M Na2 HPO4 buffer solutions have performed. The filtrate after centrifugation half-saturated with solid Am-Sulfate (A.S) then 35% saturated with solid A.S. After the partially purified enzyme dialyzed, the extract was eluted from a sephadex G-200 column equilibrated with phosphate buffer. The enzymatic activity was observed in only one peak. The optimal pH of the cabbage leaf catalase was 7-8. When the concentration of stabilized catalase increased, the reaction rate increased concomitantly. The substrate was not inhibitory to the reaction rate up to 0.1 M of H2O2 concentration. In this study Vmax and Km of cabbage leaf catalase was 31.12 μM min-1 and 25.5 mM, respectively.