Partial . Purification and Some Properties

Two polyphenoloxidases (PPO ] and PPO III, EC 1,10.3,1) were extracted and partially purified from sago palm pith by hydroxylapatite chromatography, DEAE-cellulose chromategraphy and gel filtration. Both purified isozymes gave a single activity band on polyacrylamide gel electrophoresis. The rno]ecular weights of both enzymes were estimated to be 40,OOO. Thev had the same pH optima of 6,5 but different temperature optima, 35CC for PPO I and 45"C for"PPO III. PPO I was stable at neutral to alkaline pH and PPO JII at acidic pH, PPO TII was somewhat more stab]e than PPO L when incubated at various temperatures for 15min, PPO I and PPO III oxidized well DL-epicatechin and D-catechin, respectively. Both enzyrnes were strongly inhjbited by KCN, Na-diethyldithiocarbamate and NaHS03.