半胱氨酸对马铃薯多酚氧化酶的抑制作用  

Inhibitory Effect on Potato Polyphenol Oxidase Activity by L-Cysteine

作　　者：邱龙新[1,2] 黄浩[1] 陈清西[1] 

机构地区：[1]厦门大学生物化学与生物技术系教育部细胞生物学与肿瘤细胞工程重点实验室 [2]龙岩学院生物科学与工程系,福建龙岩364000

出　　处：《食品科学》2006年第4期37-40,共4页Food Science

基　　金：福建省科技攻关课题(2004N002);福建省自然科学基金项目(B0410003)

摘　　要：马铃薯在保藏和加工过程中容易发生褐变,是因为其多酚氧化酶的作用结果。实验发现L-半胱氨酸对该酶有明显的抑制作用,它的作用可以导致马铃薯多酚氧化酶的酶促反应的迟滞时间延长,同时使稳态酶活力下降。其导致酶活力下降50%的抑制剂浓度(IC50)为100μmol/L。L-Cys对马铃薯多酚氧化酶的效应为不可逆的抑制,它作用于马铃薯多酚氧化酶活性而抑制褐色产物的产生,起到对马铃薯的保鲜作用。In this paper, L-Cysteine was discovered to have a strong inhibition on potato polyphenol oxidase activity. The existence of L-Cysteine resulted in prolonging the lag time of the enzyme reaction, while the steady-state rate of the enzyme activity decreased with the increase of concentration of L-Cysteine. The IC50, inhibitor＇s concentration leading to 50% activity lost, was estimated to be 100μmol/L. The inhibition kinetics and mechanism of L-Cysteine on the potato PPO activity have been studied. The results showed that inhibition of L-Cysteine on the enzyme is an irreversible reaction. It has a direct effect on the enzyme activity, which inhibit the production of o-quinones to stop the enzymatic browning of potato.

关 键 词：马铃薯 多酚氧化酶 半胱氨酸 抑制作用机理 

分 类 号：Q356.1[生物学—遗传学]