Function of M-line-bound creatine kinase as intramyofibrillar ATP regenerator at the receiving end of the phosphorylcreatine shuttle in muscle.
Function of M-line-bound creatine kinase as intramyofibrillar ATP regenerator at the receiving end of the phosphorylcreatine shuttle in muscle.
复制标题
M 线结合肌酸激酶作为肌肉中磷酸肌酸穿梭接收端肌原纤维内 ATP 再生器的功能。
DOI：
10.1016/s0021-9258(17)42981-4
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
H. Eppenberger
中科院分区：
文献类型：
--
作者：
T. Wallimann;T. Schlösser;H. Eppenberger
在10个洗涤循环后，0.8u.e.的肌酸激酶活性仍然结合每毫克鸡胸肌肌原纤维已被释放的可溶性肌酸激酶，线粒体，和膜。结合的肌酸激酶位于M带，并有助于该肌节结构的电子密度（Wallimann，T.，Pelloni，G.W.，华盛顿特区特纳和Eppenberger，H. M.等人（1978）Proc. Acad. Sci.联合S. A. 75，4296-4300）。通过测定肌动蛋白激活的Mg ~（2+）-ATP酶和肌酸激酶的结合反应，表明肌原纤维的M线结合肌酸激酶活性足以使肌动蛋白激活的Mg ~（2+）-ATP酶在体外水解的ATP再磷酸化。M-线结合肌酸激酶的量，从而ATP再生潜力取决于肌肉类型。在快肌中较高，在慢肌中较低。抑制肌原纤维肌酸激酶或提取的M-线结合酶废除ATP再生潜力，而不影响ATP酶活性。肌激酶、线粒体ADP/ATP转位酶和呼吸抑制剂不影响ATP再生潜力或ATP酶。M-线结合肌酸激酶，足以支持6s-1的ATP周转率每肌球蛋白头，似乎有能力的肌原纤维再生的大部分或所有的ATP水解肌原纤维ATP酶在肌肉收缩。因此，在磷酸肌酸穿梭的肌原纤维接收端的M-线结合肌酸激酶具有生理意义。
After 10 wash cycles, 0.8 u.e. of creatine kinase activity remained bound per mg of chicken pectoralis myofibrils which had been freed of soluble creatine kinase, mitochondria, and membranes. The bound creatine kinase is located at the M-band and contributes to the electron density of this sarcomeric structure (Wallimann, T., Pelloni, G.W., Turner, D.C., and Eppenberger, H. M. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 4296-4300). By measuring the combined actin-activated Mg2+-ATPase and creatine kinase reactions of myofibrils by pH-stat, it was shown that the amount of M-line-bound creatine kinase activity was sufficient to rephosphorylate the ATP hydrolyzed in vitro by the actin-activated Mg2+-ATPase. The amount of M-line-bound creatine kinase and thus the ATP regeneration potential depended on the muscle type. It was higher in fast muscles and lower in slow muscles. Inhibition of myofibrillar creatine kinase or extraction of the M-line-bound enzyme abolished the ATP regeneration potential without affecting ATPase activity. Inhibitors of myokinase, mitochondrial ADP/ATP translocase, and respiration did not affect the ATP regeneration potential or the ATPase. M-line-bound creatine kinase, sufficient to support an ATP turnover rate of 6s-1 per myosin head, seems to have the capacity for the intramyofibrillar regeneration of most or all of the ATP hydrolyzed by the myofibrillar ATPase during muscle contraction. Thus, M-line-bound creatine kinase at the myofibrillar receiving end of the phosphorylcreatine shuttle is of physiological significance.