Abstract

• Isolation and purification of catalase enzyme from Coriandrum sativum L. leaves were performed by ammonium sulphate precipitation followed by dialysis and gel filtration chromatography on Sephadex G-100. The catalase activity of the final purification steps was measured by following the dismutation of H2O2 spectrophotometrically using an extinction coefficient for H2O2 at 439 nm of 0.0113 mM-1 cm-1 . The effect of substrate concentration and enzyme concentration on the catalase-catalyzed reaction was studied. The Km value was calculated to be 5.1420 × 10-3 M H2O2, and the Vmax value was found to be 0.1308 M min-1 using the plot of Lineweaver-Burk. The activation energy (Ea) of the catalase-catalyzed reaction was calculated to be 2.978 kcal mol-1 . The reaction order (n) of the catalase-catalyzed reaction was found to be the first-order reaction. The catalase activity decreased with each hour of incubation in buffers with different pH values and temperatures. After 3 h of incubation at 40 ºC, the catalase activity was almost completely lost.