Abstract: In this study,peroxidases (PODs) of Rumex japonicus Houtt leaves were extracted and purified.Its enzymatic characteristics were studied.PODs were extracted from leaves of Rumex japonicus Houtt using the lixiviating method with a phosphate buffer.The main factors affecting extraction,including ratio of materials to buffer,buffer pH,extraction temperature and extraction duration,were evaluated and optimized by the single factor and L₉(3⁴) orthogonal experiment.In addition,PODs were purified using pH and acetone precipitation methods for further analysis of its enzymatic properties.The results showed that the optimal extraction conditions of PODs were as follows:ratio of materials to buffer of 1:40,pH 9,extraction temperature of 35 ℃,extraction duration of 35 min.Adjusting pH to 5 and adding 0.8~1 folds of acetone in the extraction solutions can get proteins with relatively high amount and high enzymatic activity.The obtained PODs had the Km of 0.12 mmol/L and 0.62×10³ mmol/L for Guaiacol and H₂O₂, respectively.Only CuSO₄ enhanced the PODs activity,while ZnSO₄, MgSO₄, CaCl₂, KCl and NaCl inhibited it.The results suggested that the extraction and purification methods of PODs were simple and effective for R.japonicus and laid a foundation for practical application of its enzymatic properties and for understanding the growth features of R.japonicus.

Key words: Rumex japonicus Houtt, peroxidase, isolation and purification, enzymatic characteristics