Isolation, Purification And Some Properties Of Polyphenol Oxidase In Wheat Bran

Polyphenol oxidase (PPO) is a Cu metalloproteinases,existing widely in the nature.polyphenol oxidase in wheat grain is the main factors causing flour food browning which not only influences the nutritional value of food,but also lows its economic value and sensory quality.At present the researches about purification and characteristics of vegetables and fruit PPO are more, wheat PPO are rarely reported.The purification and enzymology character of wheat PPO from the wheat cultivar AnNong0823were researched by This experiment with varieties of wheat bran for material, through the enzyme fluid extraction, ammonium sulfate grading salting-out, Macro-prep DEAE column chromatography, SephadexG-75column chromatography and so on.At the same time the process parameters were optimized in the process of the extraction and purification. Results showed that:1) Latifah is an effective method to extract wheat bran PPO.2) Appropriate temperature (4℃-10℃), oscillation frequency (120r/min), duration (8h-12h), soaking system PH (PH6) can stop polyphenol oxidase activity from losting in the extraction process.3) Adding3%cross-linked polyethylene pyrrole (PVPP) in Latifah system can effectively increase PPO activity.4) The optimal PH of PPO enzymatic activity for5, the optimum temperature for37℃.5) Grading ammonium sulfate precipitation can effectively increase the purification efficiency of PPO enzymatic protein.6) PPO protein after Macro-prep DEAE column chromatography and SephadexG-75column chromatography, showed a single band by SDS-PAGE, the size is respectively77KDa,78KDa and67.5KDa.