菠萝蜜过氧化物酶活性部位的研究  

Active Center of Peroxidase from Jackfruit Flesh

作　　者：陶毅明[1] 金荣仲[1] 朱华[1] 马义丽[1] 刘青波[1] 

机构地区：[1]桂林医学院生物技术学院,广西桂林541004

出　　处：《食品科学》2016年第11期103-107,共5页Food Science

基　　金：国家自然科学基金地区科学基金项目(31260214)

摘　　要：以菠萝蜜果肉过氧化物酶(peroxidase,POD)为研究对象,用丁二酮、碳化二亚胺(N-ethylN’-3-dimethylaminopropyl carbodiimide,EDC)、N-乙酰咪唑(N-acetylimidazole,NAI)、β-巯基乙醇(β-mercaptoethanol,MT)、对-氯汞苯甲酸(parachloro-mercuri-benzoate,p CMB)和焦碳酸二乙酯(diethylpyrocarbonate,DEPC)对POD进行化学修饰,研究酶活性必需基团。结果表明,丁二酮、EDC和NAI对酶活力无显著影响,说明精氨酸、羧基和酪氨酸与酶活力无关;p CMB、DEPC和β-巯基乙醇强烈抑制酶活性,说明半胱氨酸和组氨酸是酶活性的必需基团,二硫键对酶活性有重要贡献。动力学分析和底物保护实验表明,DEPC为POD的竞争性抑制剂,组氨酸位于酶活中心。In order to investigate the essential groups for peroxidase(POD) activity from jackfruit flesh, diacetyl, N-ethylN'-3-dimethylaminopropylcarbodiimide(EDC), N-acetylimidazole(NAI), β-mercaptoethanol(MT), parachloro-mercuribenzoate(p CMB) and diethyl pyrocarbonate(DEPC) were used to modify the POD enzyme. The results revealed that diacetyl, EDC and NAI showed no significant impact on POD activity, indicating that Arg, carboxyl and Lys had no association with the enzyme activity. However, p CMB, DEPC and MT strongly inhibited POD activity, indicating that Cys and His were the essential groups for its activity, and disulfide bond played a very important role in the enzyme activity. Enzymatic kinetics and substrate protection indicated that DEPC was a competitive inhibitor for POD, and the His residue was located at the enzyme active center.

关 键 词：过氧化物酶 菠萝蜜 酶活中心 必需基团 化学修饰 

分 类 号：Q55[生物学—生物化学]