蛋白酶体及其介导的泛素-蛋白酶体途径对宰后秦川牛肉蛋白的降解作用  

Postmortem Degradation of Qinchuan Beef Protein by Proteasome and Its Mediated Ubiquitin-Proteasome Pathway

作　　者：胡丽筠 张倩[1] 陈雪妍 王金霞 李荣[1] 李亚蕾[1] 罗瑞明[1] HU Lijun;ZHANG Qian;CHEN Xueyan;WANG Jinxia;LI Rong;LI Yaei;LUO Ruiming(School of Food and Wine,Ningxia University,Yinchuan 750000,China)

机构地区：[1]宁夏大学食品与葡萄酒学院,宁夏银川750000

出　　处：《食品科学》2023年第24期112-117,共6页Food Science

基　　金：国家自然科学基金地区科学基金项目(32160535);宁夏回族自治区重点研发项目(2017BY068)。

摘　　要：以宰后4℃条件下不同贮藏期的秦川牛背最长肌为研究对象,通过注射蛋白酶体抑制剂MG-132,测定宰后贮藏过程中蛋白的降解情况、蛋白酶体活性、泛素蛋白含量以及微观结构变化,探究蛋白酶体介导的泛素-蛋白酶体途径(ubiquitin-proteasome pathway,UPP)对宰后秦川牛肉贮藏过程的影响,为宰后牛肉品质的精确调控途径提供理论支撑。主要研究结果:随着贮藏时间的延长,MG-132组中的蛋白酶体活性低于对照组,总可溶性蛋白含量、泛素蛋白含量高于对照组;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,MG-132组总可溶性蛋白在40~250 kDa之间的蛋白条带整体深于对照组;MG-132组的牛背最长肌结构保留较好,Z线以及明暗带的边界都比对照组清晰,且总可溶性蛋白与泛素蛋白含量变化呈显著正相关(P<0.05)。综上所述,MG-132抑制宰后秦川牛肉中蛋白酶体活性以及UPP中泛素化蛋白的降解,进而改变宰后秦川牛肉中蛋白的降解,减少肌肉结构的破坏,说明UPP对宰后肉质的形成具有潜在作用,蛋白酶体可以单独降解蛋白,破坏宰后牛肉肌原纤维结构,还可以通过介导UPP影响宰后牛肉蛋白的降解,最终影响宰后牛肉的品质。In this study,the Longissimus dorsi muscle of Qinchuan cattle was injected with the proteasome inhibitor MG-132 immediately postmortem and then stored at 4℃.The effect of the ubiquitin-proteasome pathway(UPP)on protein degradation as well as changes in the proteasome activity,ubiquitin content and microstructure of the muscle during postmortem storage was explored in order to provide theoretical support for precise postmortem regulation of beef quality.With the extension of storage time,proteasome activity was lower and the contents of total soluble protein and ubiquitin were higher in the MG-132 group than in the control group.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)results showed that the band intensity of total soluble proteins between 40 and 250 kDa was greater in the MG-132 group than in the control group;muscle structure was better preserved in the MG-132 group,and the Z line and the boundary between light and dark bands were clearer than those in the control group.The contents of total soluble protein and ubiquitin showed a significantly positive correlation(P<0.05).In conclusion,postmortem injection of MG-132 inhibited the proteasome activity and the degradation of ubiquitinated proteins in the UPP in Qinchuan beef,which in turn altered protein degradation and attenuated muscle damage.This suggests that the UPP has a potential role in meat quality formation;the proteasome not only degrades proteins by itself alone to destroy beef myofibrillar structure,but also influences postmortem beef protein degradation through mediating the UPP,ultimately affecting postmortem beef quality.

关 键 词：牛 蛋白酶体抑制剂MG-132 蛋白酶体 泛素-蛋白酶体途径 

分 类 号：TS251.52[轻工技术与工程—农产品加工及贮藏工程]