EFFECT OF POSTMORTEM STORAGE AND CALCIUM ACTIVATED FACTOR ON THE MYOFIBRILLAR PROTEINS OF BOVINE SKELETAL MUSCLE
EFFECT OF POSTMORTEM STORAGE AND CALCIUM ACTIVATED FACTOR ON THE MYOFIBRILLAR PROTEINS OF BOVINE SKELETAL MUSCLE
复制标题
死后储存和钙激活因子对牛骨骼肌肌原纤维蛋白的影响
DOI：
--
复制
发表时间：
1977
期刊：
影响因子：
--
通讯作者：
D. E. Goll
中科院分区：
文献类型：
--
作者：
D. Olson;F. C. Parrish;W. Dayton;D. E. Goll
使用十二烷基硫酸钠 (SDS) 聚丙烯酰胺凝胶电泳分析从牛死时最长肌 (L)、半腱肌 (ST) 和腰大肌 (PM) 肌肉以及死后储存 (2 和 25°C) 1、2、3、6 和 10 天时分离的肌原纤维。肌钙蛋白亚基之一肌钙蛋白 T 在 25°C 死后保存期间从 L 和 ST 肌肉中消失，同时出现了 30,000 道尔顿的成分。在 25°C 下储存肌肉加速了 L 和 ST 肌肉肌原纤维的这些变化，但 PM 肌肉的 SDS 聚丙烯酰胺凝胶在 2 或 25°C 储存期间几乎没有变化。从牛 L、ST 和 PM 肌肉中分离出 Ca2+ 激活因子 (CAF) 的粗制剂。 L 和 ST 肌肉的总 CAF 活性较高且相似，但 PM 肌肉的 CAF 总活性不到 L 和 ST 肌肉的一半。将纯化的 CAF 与从死时肌肉中分离出的肌原纤维一起孵育，会导致 Z 盘降解和肌钙蛋白 T 消失，并同时出现 30,000 道尔顿成分。纯化的 CAF 与纯化的肌钙蛋白一起孵育导致肌钙蛋白-T 降解为 30,000 道尔顿成分，这表明整个肌小纤维中的 30,000 道尔顿成分源自肌钙蛋白-T。 CAF 对 Z 盘和肌钙蛋白-T 降解以及 L、ST 和 PM 肌肉中 CAF 相对总活性的影响与死后储存对肌原纤维断裂、肌小纤维蛋白降解和 WB 剪切力值的影响相似。这些平行效应表明 和 是有限的。肌原纤维蛋白的特异性蛋白水解是由肌细胞内源性 Ca2+ 激活因子引起的。
Myofibrils isolated from bovine longissimus (L), semitendinosus (ST) and psoas major (PM) muscles at-death and at 1, 2, 3, 6 and 10 days postmortem storage (2 and 25°C) were analyzed with sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. One of the subunits of troponin, troponin T, disappeared from L and ST muscle during postmortem storage at 25°C, and concurrently a 30,000 dalton component appeared. Storage of muscles at 25°C accelerated these changes in myofibrils from L and ST muscles, but SDS polyacrylamide gels of PM muscle changed little during storage at either 2 or 25°C. Crude preparations of a Ca2+-activated factor (CAF) were isolated from bovine L, ST and PM muscles. Total CAF activity was high and similar in L and ST muscles, but PM muscle contained less than half the total CAF activity of L and ST muscles. Incubation of purified CAF with myofibrils isolated from at-death muscle caused Z-disk degradation and disappearance of troponin T and the simulataneous appearance of a 30,000 dalton component. That incubation of purified CAF with purified troponin caused degradation of troponin-T to a 30,000-dalton component indicates that the 30,000-dalton component in whole myotibrils originates from troponin-T. The effects of CAF on Z-disk and troponin-T degradation and the relative total activity of CAF in L, ST and PM muscles are similar to the effects of postmortem storage in myofibril fragmentation, myotibrillar protein degradation and WB shear force values. These parallel effects indicate that the limited and. specific proteolysis of myofibrillar proteins is caused by a Ca2+-activated factor endogenous to the muscle cell.