富士苹果中多酚氧化酶活性的中心必需基团与抑制动力学  

Researches on Essential Groups of Enzyme Active Site and Inhibition Kinetics of Polyphenol Oxidase from Fuji Apple

作　　者：彭益强[1] 邓峰[1] 刘宇[1] 刘鹏[1] 

机构地区：[1]华侨大学工业生物技术福建省高等学校重点实验室,福建厦门361021

出　　处：《华侨大学学报（自然科学版）》2012年第1期51-54,共4页Journal of Huaqiao University(Natural Science)

基　　金：中央高校基本科研业务费专业资金项目(10HZR12)

摘　　要：以源于苹果的多酚氧化酶(PPO)为对象,选取溴乙酸、乙酰丙酮、N-溴代琥珀酰亚胺、1,4-二硫代苏糖醇和对氯汞苯甲酸等具有相对专一性的氨基酸基团修饰剂,研究PPO的酶活性中心必需基团,并确定乙醇对PPO的抑制动力学特性.结果表明:富士苹果中的PPO蛋白结构中酶活性中心必需基团有组氨酸的咪唑基、精氨酸的胍基与色氨酸残基.抑制动力学实验表明:乙醇通过与PPO酶活中心基团的结合抑制PPO酶活性,其对PPO的半抑制浓度(IC50)为0.14mmol.L-1,抑制类型为可逆的竞争性抑制.In this paper,chemical modifying agents,such as BrAC,Hacac,NBS,DTT and pCMB,which were relative specific to amino acid groups,were selected to study the essential groups of polyphenol oxidas（PPO） active site and the inhibition kinetics of ethanol to PPO.The result showed that the essential groups of PPO active site,which came from Fuji apple,composed of imidazole of His,guanidinium of Arg and Trp residue.Inhibition kinetics experiment revealed that the ethanol could inhibited PPO activity by combining with the groups from enzyme active site.The IC50 was 0.14 mmol·L-1 and the inhibition mode was reversible competitive inhibition.

关 键 词：多酚氧化酶 酶活性中心 必需基团 可逆抑制 

分 类 号：S661.6[农业科学—果树学] Q946.5[农业科学—园艺学]