Purificiation and Some Properties of Polyphenol Oxidase from Van Apple(Golden Delicious)

摘要

Polyphenol oxidase was isolated from van apple,with a 4.0-fold purification of polyphenol oxidase by ammonium sulfate and DEAE cellulose being achieved.The optimum pH was 4 and for this enzyme,the optimum temperature was 50deg C.V_(max)and K_m values were found of Lineweaver-Burk graphs.Potassium cyanide,benzoic acid,citric acid,MnCl_2,NaCl,NaNO_2 and CuSO_4 were used as inhibitors.The enzyme activity was inhibited by benzoic acid,CuSO_4 and NaCl,polyphenol oxidase activity at 10 mM,whereas NaNO_2,citric acid,KCN and MnCl_2 enhanced by polyphenol oxidase activity at 10 mM.