Pruidze G N, Grigorashvili G Z, Chachus L Sh, Tokhadze M V
Biokhimiia. 1976 Oct;41(10):1819-28.
Purification of fractions of tea leaves peroxidase is described. During ion-exchange chromatography on DEAE- and CM-cellulose peroxidase is eluted into six fractions, differing in their electrophoretic properties. The enzyme showed optimal activity at pH 4.1-5.0, when the enzyme fractions of guaiacol adsorbed on DEAE-cellulose were used as a substrate; in case of enzyme fractions adsorbed on CM-cellulose it was observed within pH range of 5.4-6.2. The dependence curves of the initial rate of the reaction on the substrate concentration were S-shaped in case of the latter fractions. Peroxidase is shown to catalyze the oxidation of tea catechins; its activity is inhibited by the products of their condensation. The catalytic effect of the enzyme on the oxidation of phenolic acids, e.g. chlorogenic, caffeic and gallic, was far stronger than on that of tea catechins, pyrogallol and pyrocatechin. It was established that two fractions of the enzyme possess predominantly the phloroglucinol oxidase activity, whereas the other fractions do not catalyze the oxidation of phloroglucin. The molecular weights of some peroxidase fractions estimated by polyacryl amide gel electrophoresis are 26.000+/-1.100, 45.00+/-1.200 and 50.000+/-1.500.
本文描述了茶叶过氧化物酶各组分的纯化过程。在DEAE -纤维素和CM -纤维素上进行离子交换色谱时，过氧化物酶被洗脱成六个组分，它们的电泳性质不同。当以吸附在DEAE -纤维素上的愈创木酚酶组分作为底物时，该酶在pH 4.1 - 5.0时表现出最佳活性；而当以吸附在CM -纤维素上的酶组分作为底物时，最佳活性出现在pH 5.4 - 6.2范围内。对于后一组分，反应初始速率对底物浓度的依赖曲线呈S形。结果表明，过氧化物酶可催化茶叶儿茶素的氧化，其活性受到儿茶素缩合产物的抑制。该酶对酚酸（如绿原酸、咖啡酸和没食子酸）氧化的催化作用远强于对茶叶儿茶素、连苯三酚和邻苯二酚氧化的催化作用。已确定该酶的两个组分主要具有间苯三酚氧化酶活性，而其他组分不催化间苯三酚的氧化。通过聚丙烯酰胺凝胶电泳估算的一些过氧化物酶组分的分子量分别为26,000±1,100、45,000±1,200和50,000±1,500。
