Purification and characterization of polyphenol oxidase (PPO) from eggplant (Solanum melongena)
Purification and characterization of polyphenol oxidase (PPO) from eggplant (Solanum melongena)
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DOI：
10.1016/j.foodchem.2012.03.098
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发表时间：
2012-10-15
期刊：
影响因子：
8.8
通讯作者：
Sharma, Arun
中科院分区：
文献类型：
--
作者：
Mishra, Bibhuti B.;Gautam, Satyendra;Sharma, Arun
茄子(Solanum Melongena)富含多酚氧化酶(PPO)，其在切花和采后加工过程中会因酶促褐变而对品质产生负面影响。来自天然或合成来源的PPO抑制剂被用来解决这个问题。使用标准的层析程序将PPO的一个异构体纯化了259倍。PPO为112 kDa的同源二聚体。该酶对4-甲基邻苯二酚表现出很低的K-m(0.34 mM)和很高的催化效率(3.3×10(6))。底物专一性依次为：4-甲基儿茶酚GT、叔丁基儿茶酚GT、二氢咖啡酸GT、邻苯二酚。半胱氨酸盐酸盐、偏亚硫酸钾、抗坏血酸、异抗坏血酸、间苯二酸和曲酸对PPO活性有竞争性抑制作用，柠檬酸和叠氮化钠对PPO活性有混合抑制作用。半胱氨酸盐酸盐被发现是一种很好的缓蚀剂，其缓蚀剂的低常数为1.8亩M(C)2012爱思唯尔有限公司。版权所有。
Eggplant (Solanum melongena) is a very rich source of polyphenol oxidase (PPO), which negatively affects its quality upon cutting and postharvest processing due to enzymatic browning. PPO inhibitors, from natural or synthetic sources, are used to tackle this problem. One isoform of PPO was 259-fold purified using standard chromatographic procedures. The PPO was found to be a 112 kDa homodimer. The enzyme showed very low K-m (0.34 mM) and high catalytic efficiency (3.3 x 10(6)) with 4-methyl catechol. The substrate specificity was in the order: 4-methyl catechol > tert-butylcatechol > dihydrocaffeic acid > pyrocatechol. Cysteine hydrochloride, potassium metabilsulfite, ascorbic acid, erythorbic acid, resorcylic acid and kojic acid showed competitive inhibition, whereas, citric acid and sodium azide showed mixed inhibition of PPO activity. Cysteine hydrochloride was found to be an excellent inhibitor with the low inhibitor constant of 1.8 mu M. (C) 2012 Elsevier Ltd. All rights reserved.