美味牛肝菌PPO酶学特性及其抑制机理  

Enzymatic Characteristics and Inhibition Mechanism of PPO from Boletus edulis

作　　者：资璐熙 向仕聪 徐柠檬 李为兰 秦粉 郭磊 ZI Luxi;XIANG Shicong;XU Ningmeng;LI Weilan;QIN Fen;GUO Lei(School of Life Science,Southwest Forestry University,Kunming 650224,China)

机构地区：[1]西南林业大学生命科学学院,昆明650224

出　　处：《西北农业学报》2025年第2期290-299,共10页Acta Agriculturae Boreali-occidentalis Sinica

基　　金：云南省科技厅农业联合专项(202101BD070001-054);云南省科技厅基础研究计划(202101AT070042);国家自然科学基金(32260639)。

摘　　要：以美味牛肝菌为原料,对PPO进行分离纯化后研究其酶学特性,在此基础上,采用动力学模型和Lineweaver-Burk作图法对PPO热失活动力学和抑制剂作用机理进行分析。结果表明:美味牛肝菌PPO酶促反应产物在407 nm处有最大吸收峰,与邻苯二酚亲和力最强,酶促反应动力学参数K_(m)=9.41 mmol/L,V_(max)=196.08 U/min,PPO最适底物为50 mmol/L邻苯二酚,最适pH为6.8,最适反应温度和时间分别为45℃、7 min。PPO在90℃下酶失活最快,其动力学参数为k=2.5045 min^(-1)、D=0.9420 min、T_(1/2)=0.2768 min;70℃~90℃下美味牛肝菌PPO失活活化能E_(a)=130.283 kJ/mol。偏重亚硫酸钠的抑制类型属于非竞争性抑制,抗坏血酸和L-半胱氨酸的抑制类型属于竞争性抑制。热处理和添加抑制剂能有效抑制PPO酶活力,研究结果为美味牛肝菌采后储藏及加工过程中的品质控制提供了一定的参考依据。To investigate enzymatic characteristics of PPO,PPO from Boletus edulis was isolated and purified.Based on this study,the thermal inactivation kinetics and inhibition mechanism of PPO were analyzed using kinetic models and Lineweaver-Burk plot methods.The results showed that the enzymatic reaction product of PPO from Boletus edulis had the maximum absorption wavelength at 407 nm,PPO and catechol had the strongest affinity,and the kinetic parameters of the enzymatic reaction were K_(m)=9.41 mmol/L,V_(max)=196.08 U/min.The optimal substrate of PPO was 50 mmol/L catechol,the optimum pH was 6.8,the optimal reaction temperature and time were 45℃and 7 min,respectively.The PPO enzyme inactivation was fastest at 90℃,and the kinetic parameters were k=2.5045 min^(-1),D=0.9420 min,T^(1/2)=0.2768 min.The activation energy(E_(a))for PPO inactivation between 70℃to 90℃was 130.283 kJ/mol.Sodium metabisulfite showed noncompetitive inhibition,while ascorbic acid and L-cysteine showed competitive inhibition.PPO activity can be effectively inhibited by heat treatment and the addition of inhibitors.These findings provide a reference for the quality control of Boletus edulis during postharvest storage and processing.

关 键 词：美味牛肝菌 多酚氧化酶 酶学特性 分子对接 热失活 抑制剂机理 

分 类 号：TS219[轻工技术与工程—粮食、油脂及植物蛋白工程]