Purification, characterization and selected inhibition properties of peroxidase from haricot bean (Phaseolus vulgaris L.)

In this study, a cationic soluble peroxidase (POD) was homogeneously purified and biochemically characterized. The enzyme purification involved the combination of (NH4)2SO4 precipitation, CM-Sephadex cation exchange, and gel filtration chromatography. The purity of the enzyme was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, and one single prominent band was obtained with a molecular weight of approximately 45 kDa. The thermal and pH stability showed that the enzyme was stable at pH 5.0 and at 40°C, respectively. The activity remained stable at pH 4.0 at least for 10 days. Km and Vmax values were calculated from Lineweaver–Burk graph for each substrate. POD exhibited Km values of 0.0154 and 0.065 mM for guaiacol and H2O2, respectively. The enzyme was highly inhibited by sodium azide. This study could enrich the literature regarding the properties of POD from haricot bean that could be applicable to biomedical analysis. © 2017 Taylor & Francis Group, LLC.