Translated Title
Purification and Characterization of Polyphenol Oxidase from Fresh Lotus Seed of Nelumbo nucifera Gaertn
Translated Abstract
Objective: The main purpose of this research is purification and characterization of the polyphenol oxidase from fresh lotus seeds, which could probably provide practical application in inhibiting the PPO activity and preventing enzymatic browning in the process of transportation, processing and storage of fresh Lotus Seeds.Methods: The polyphenol oxidase (PPO) was extracted and further purified by the procedures including ammonium sulfate precipitation and affinity chromatography on Affi-gel blue gel.SDS-PAGE was used to analyze the molecular weight of PPO.Kinetic study, stability and the effects of inhibitors on the activity of PPO were performed when catechol was used as substrate.Results: A polyphenol oxidase was purified from fresh lotus seeds with a molecular mass of 38.6 kDa by SDS-PAGE.The PPO performed optimal activity in 20℃ and pH 7.0 for catechol substrate.Kinetic studies showed that the Km and Vmax values were 6.04 mM and 416.67 U respectively.The enzymatic activity could be mainly maintained up to 40℃ and pH 4.0-8.0 and was indiscernible when the temperature reached 80℃.The activity of PPO could be inhibited by 50 mM of thiourea, EDTA·2Na, SDS, citric acid, ascorbic acid, sodium sulfite and sodium thiosulfate.Metal ions including Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Zn2+ could inhibit the activity of PPO while Cu2+ performed obvious enhancement.Conclusion: A polyphenol oxidase was purified from fresh lotus seeds and the kinetic study was performed.This research may provide theoretical basis for the control of enzymatic browning induced by PPO in lotus seeds.
Translated Keyword
Catechol
Inhibitors
Kinetic Study
Lotus Seeds
Polyphenol Oxidase
Conference Name
科技与产业对接——中国食品科学技术学会第十届年会暨第七届中美食品业高层论坛
