1989 Volume 36 Issue 7 Pages 597-602
Polyphenol oxidase (EC. 1.10.3.1, PPO) of defatted soybean has been purified by ammonium sulfate fractionation, DEAE-Toyopearl column, Con A-sepharose column, Phenyl-sepharose CL-4B column and Mono Q column chromatography. The purified enzyme oxidized pyrogallol and phloroglucinol. The enzyme fraction showed maximum absorbance at 403nm and exhibited brown color. The enzyme also has peroxidase (EC 1.11.1.7, POD) activity. Through the purification procedures, PPO and POD activities have been eluted in the same fraction and the ratio of the both specific activities stayed constant. The molecular weight of the purified enzyme is estimated to be 47000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH of POD and PPO are 5.5 and over 7.5, respectively. Both activities are stable at 80°C for 10min and are inhibited by potassium cyanide and L-ascorbic acid.
