Polyphenol oxidase in tea leaves was fractionated to three components, called A-I, A-II and B, by the combination of DEAE and CM-cellulose column chromatographies. They exhibited different migration on starch-gel electrophoregram at pH 5.0. The results of CM-cellulose chromatography and starch-gel electrophoresis indicated that A-I and A-II were basic proteins but B was not. Specific activities of purified components, A-I and A-II, were increased to about 200 and 140 times as much as that of tea leaf homogenate, respectively.
Optimum pH for A-I and A-II are 5.1 and 4.6, respectively. A-I was found to oxidize o-diphenol rather well, whereas, A-II oxidized well both vicinal-triphenol and o-diphenol. The activity of the above two enzymes was inhibited by a high concentration of substrate. Optimum temperature of enzymic reaction was about 35°C.

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