THE ROLE OF CA-2+-DEPENDENT PROTEASES (CALPAINS) IN POSTMORTEM PROTEOLYSIS AND MEAT TENDERNESS
THE ROLE OF CA-2+-DEPENDENT PROTEASES (CALPAINS) IN POSTMORTEM PROTEOLYSIS AND MEAT TENDERNESS
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DOI：
10.1016/0300-9084(92)90122-u
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发表时间：
1992-03-01
期刊：
影响因子：
3.9
通讯作者：
KOOHMARAIE, M
中科院分区：
文献类型：
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作者：
KOOHMARAIE, M
本手稿总结了我们实验室关于内源蛋白酶在死后蛋白水解导致肉嫩化中的作用的研究结果。关键肌原纤维蛋白的蛋白水解是与肉嫩化相关的骨骼肌超微结构变化的主要原因。蛋白酶应具有以下特征，被认为是引起死后变化的可能候选者：i) 位于骨骼肌细胞内：能够接触底物，即肌原纤维，以及 iii) 能够水解在死后储存期间降解的相同蛋白质。在位于骨骼肌细胞内且迄今为止已表征的蛋白酶中，只有钙蛋白酶具有所有上述特征。我们实验室进行的大量实验表明，钙依赖性蛋白水解系统（钙蛋白酶）负责死后蛋白水解。其中一些证据包括：1) 将肌肉切片与含有 Ca2+ 的缓冲液一起孵育可加速死后蛋白水解； 2) 肌肉切片与 Ca2+ 螯合剂一起孵育可抑制死后蛋白水解； 3) 用氯化钙溶液灌注或注射屠体可加速宰后蛋白水解和嫩化过程，从而不再需要宰后储存超过 24 小时以确保肉嫩度： 4) 用氯化锌（钙蛋白酶的强效抑制剂）灌注屠体，阻止宰后蛋白水解和嫩化过程； 5)给羔羊饲喂β-肾上腺素能激动剂会导致钙蛋白酶系统的蛋白水解能力降低，从而导致死后蛋白水解率降低并产生坚韧的肉。基于这些结果，我们得出结论，钙蛋白酶是负责死后蛋白水解的主要蛋白水解系统，并且钙蛋白酶的主要调节剂之一是其内源性抑制剂钙蛋白酶抑制素。
This manuscript summarizes research results from our laboratory regarding the role of endogenous proteases in post mortem proteolysis resulting in meat tenderization. Proteolysis of key myofibrillar proteins is the principal reason for ultrastructural changes in skeletal muscle associated with meat tenderization. Proteases should have the following characteristics to be considered as possible candidates for bringing about post mortem changes: i) to be located within skeletal muscle cells: in to have access to the substrate ie, myofibrils), and iii) to be able to hydrolyze the same proteins that are degraded during post mortem storage. Of the proteases located within skeletal muscle cells and thus far characterized, only calpains have all of the above characteristics. Numerous experiments conducted in our laboratory have indicated that the calcium-dependent proteolytic system (calpains) is responsible for post mortem proteolysis. Some of this evidence includes: 1) incubation of muscle slices with buffer containing Ca2+ accelerates post mortem proteolysis; 2) incubation of muscle slices with Ca2+ chelators inhibits post mortem proteolysis; 3) infusion or injection of carcasses with a solution of calcium chloride accelerates post mortem proteolysis and the tenderization process such that post mortem storage beyond 24 h to ensure meat tenderness is no longer necessary: 4) infusion of carcasses with zinc chloride, a potent inhibitor of calpains, blocks post mortem proteolysis and the tenderization process; and 5) feeding a beta-adrenergic agonist to lambs results in a reduction of the proteolytic capacity of the calpain system, which leads to a decreased rate of post mortem proteolysis and produces tough meat. Based on these results, we have concluded that calpains are the main proteolytic system responsible for post mortem proteolysis, and that one of the main regulators of calpains is their endogenous inhibitor, calpastatin.