摘要
对金银花多酚氧化酶底物特异性和不同抑制剂的抑制效应进行了动力学分析,结果表明:金银花多酚氧化酶的最适作用底物为绿原酸,Km值为0.0059 mmol/L。维生素C、4-己基间苯二酚、L-半胱氨酸对多酚氧化酶的抑制均属可逆抑制,其抑制类型分别属于混合性、竞争性、反竞争性,对游离酶的抑制常数KI分别为1.620、4.587、0 mmol/L,对酶-底物络合物的抑制常数KIS分别为1.995、0、3.780 mmol/L;柠檬酸的抑制效应属不可逆抑制。维生素C、4-己基间苯二酚、L-半胱氨酸、柠檬酸对金银花多酚氧化酶半抑制浓度分别为0.062、0.053、0.140、0.048 mmol/L。
The aim of this work was to study substrate specificity and inhibition kinetics of ascorbic acid, 4-hexylresorcinol, L-cysteine and citric acid on PPO obtained from honeysuckle. The results show that the best substrate is chlorogenic acid because of the lowest Km value 0. 0059 mmol/L; ascorbic acid, 4-hexylresorcinol and L-cysteine demonstrate reversible inhibition, and their IC50 values are 0. 062, 0. 053,0. 140 mmol/L. Citric acid shows irreversible inhibition to PPO with IC50 value of 0. 048 mmol/L. Lineweaver-Burk plotting show that ascorbic acid, 4-hexylresorcinol and L-cysteine are mixed-type, non-competitive and anti-competitive inhibitors, with the inhibition constants K1 of 1. 620, 4. 587, 0 mmol/L, and KIS of 1. 995, 0, 3. 780 mmol/L, respectively.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2014年第7期202-208,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
NSFC-河南人才培养联合基金资助项目(U1304330)
关键词
金银花
多酚氧化酶
底物特异性
抑制剂
动力学
Honeysuckle Polyphenol oxidase Substrate specificity Inhibitor Kinetic
