Partial purification and biochemical characterization of peroxidase from rosemary (Rosmarinus officinalis L.) leaves

In this study, it is aimed to purify POD from leaves of Rosmarinus officinalis L. and determine its some biochemical properties. PODs are a group of oxidoreductase enzymes that catalyze the oxidation of a wide variety of phenolic compounds in the presence of hydrogen peroxide as an electron acceptor. In this investigation, POD was purified 9.3-fold with a yield of 32.1% from the leaves of Rosemary by ammonium sulfate precipitation and ion-exchange chromatography. The enzyme biochemical properties, including the effect of pH, temperature and ionic strength were investigated with guaiacol as an electron donor. For substrate specificity investigation of the enzyme, Michaelis constant and the maximum velocity of an enzymatic reaction values for substrates guaiacol and 3,3', 5,5'-TetraMethyle-Benzidine were calculated from the Lineweaver-Burk graphs. The POD optimum pH and temperature were 6.0 and 40°C. The POD activity was maximal at 0.3 M of sodium phosphate buffer concentration (pH 6.0). Sodium dodecyl sulphate polyacrylamide gel electrophoresis was performed for molecular weight (Mw) determination and Mw of the enzyme was found to be 33 kDa. To investigate the homogeneity of the POD, native-PAGE was done and a single band was observed. The stability against high temperature and extreme pH demonstrated that the enzyme could be a potential POD source for various applications in the medicine, chemical and food industries.