菠菜叶过氧化物酶的热失活及其动力学特性  

Thermal Inactivation and Kinetic Characterisation of Peroxidase from Spinach Leaves

作　　者：荣可瑜 张宁 许芳芳 孙美琦 周南南 潘诗雯 范晓玉 宋莹莹 陈义勇[1] 黄友如[1] RONG Keyu;ZHANG Ning;XU Fangfang;SUN Meiqi;ZHOU Nannan;PAN Shiwen;FAN Xiaoyu;SONG Yingying;CHEN Yiyong;HUANG Youru(School of Biological Science and Food Engineering,Changshu Institute of Technology,Changshu 215500;School of Environment and Bioengineering,Nantong College of Science and Technology,Nantong 226007,China)

机构地区：[1]常熟理工学院生物与食品工程学院,江苏常熟215500 [2]南通科技职业学院环境与生物工程学院,江苏南通226007

出　　处：《常熟理工学院学报》2025年第2期46-53,共8页Journal of Changshu Institute of Technology

摘　　要：以新鲜菠菜叶为原料,提取菠菜叶过氧化物酶(peroxidase,POD),探讨最适pH、最适温度、反应活化能、K_(m)与V_(max)、热稳定性及热变性活化能等酶学特性,特别是热处理对其POD活性的影响及其相关动力学的研究.结果显示,以邻苯二胺作为POD的氢供体底物,H_(2)O_(2)为过氧化物底物,菠菜叶POD的最适pH为7.0,最适反应温度为30℃,反应活化能为29.49 kJ/mol.作为双底物反应,以邻苯二胺为底物时,该酶K_(m)值为1.976 mmol/L,V_(max)为120.48 U;以H_(2)O_(2)为底物时,该酶K_(m)值为3.573 mmol/L,V_(max)为133.33 U.热失活研究显示出一级失活动力学特征,Arrhenius作图得到一条斜率相当于168.47 kJ/mol的POD热变性活化能的直线.菠菜叶POD的热失活速度在55℃~60℃出现了跳跃式变化(速度常数k从-0.042变为-0.286),60℃以后,菠菜叶POD对温度变化敏感,高温使得菠菜叶POD热不稳定部分的变性速度加快.Fresh spinach leaves were used as raw material to extract POD,and its enzymatic properties such as optimal pH,optimal temperature,catalytic activation energy,K_(m) and V_(max),thermal stability and thermal denaturation activation energy were discussed.In particular,the influence of heat treatment on POD activity and its related kinetics were studied.The results showed that with o-phenylenediamine as the hydrogen donor substrate of POD,H_(2)O_(2) as the peroxide substrate,the optimal pH was 7.0,the optimal reaction temperature was 30℃,and the activation energy of the catalytic reaction was 29.49 kJ/mol in spinach leaves POD.As a double substrate reaction,the Km value of the enzyme was 1.976 mmol/L and Vmax was 120.48 U when o-phenylenediamine was used as substrate.When H_(2)O_(2) was used as substrate,the K_(m) value of the enzyme was 3.573 mmol/L and V_(max) was 133.33 U.The thermal inactivation study showed first-order inactivation kinetic characteristics,and Arrhenius plotted a straight line with a slope equivalent to 168.47 kJ/mol of POD enzyme thermal denaturation activation energy.There was a jump change(the velocity constant k being from -0.042 to-0.286)between 55℃ and 60℃ in the thermal inactivation rate of spinach leaves POD.After 60℃,POD in spinach leaves was sensitive to temperature change,and the denaturation rate of the thermally unstable part of POD in spinach leaves was accelerated by increasing temperature.

关 键 词：菠菜 过氧化物酶 热失活 动力学特征 活化能 

分 类 号：TS201.21[轻工技术与工程—食品科学] TQ645.99[轻工技术与工程—食品科学与工程]