Purification and Partial Biochemical Characterization of Polyphenol Oxidase from Phthonandria atrineata(Butler)

The kinetic properties of polyphenol oxidase(PPO) in Phthonandria atrineata(Butler) were studied after the enzyme was partially purified by saturated(NH4)2SO4 and Sephadex G-100 gel filtration.The results showed that a 6.28-fold purification was achieved from the crude enzyme.The affinities of PPO with the substrates pyrogallol,catechol and L-dopamine(L-DOPA) were different,the Km with the three substrates being 9.64,6.82 and 4.30mmol/L,respectively.The optimum pH was 7.0 and the best temperature was 37 ℃ for the tested PPO.All the inhibitors studied showed,in different degrees,inhibitory effects on PPO activity.In addition,this enzyme proved to be comparatively sensitive to EDTA and metal ions.