横纹肌的舒张蛋白系统。肌钙蛋白复合体分解为抑制因子和钙离子敏感因子及其与原肌球蛋白的关系。

The relaxing protein system of striated muscle. Resolution of the troponin complex into inhibitory and calcium ion-sensitizing factors and their relationship to tropomyosin.

作者信息

Schaub M C, Perry S V

出版信息

Biochem J. 1969 Dec;115(5):993-1004. doi: 10.1042/bj1150993.

DOI:10.1042/bj1150993

PMID:4243353

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1185242/

Abstract

A method involving isoelectric precipitation and chromatography on SE-Sephadex (sulphoethyl-Sephadex) is described for the preparation of the troponin complex free of tropomyosin from low-ionic-strength extracts of natural actomyosin and myofibrils. 2. Purified troponin complex required tropomyosin to inhibit the Mg(2+)-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin in the presence of ethanedioxybis(ethylamine)tetra-acetate. An upper limit of 35000 for the ;molecular weight' of the troponin complex was derived from the amounts required to bring about 50% of the maximum inhibition of the Mg(2+)-stimulated adenosine triphosphatase activity of desensitized actomyosin of known concentration. 3. In the presence of dissociating reagents the troponin complex could be dissociated into inhibitory and Ca(2+)-sensitizing factors, which could be isolated separately on SE-Sephadex. The inhibitory factor inhibited the Mg(2+)-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin independently of the concentration of free Ca(2+) in the medium. 4. The Ca(2+)-sensitizing factor changed its electrophoretic mobility on polyacrylamide gel in the presence of ethanedioxybis(ethylamine)tetra-acetate. It formed a complex with the inhibitory factor at low ionic strength and the original biological activity of the troponin complex could be restored on mixing the inhibitory factor with the Ca(2+)-sensitizing factor in the ratio of about 3:2. 5. Evidence is presented indicating that the ability of tropomyosin preparations to restore relaxing-protein-system activity to the troponin complex and their inhibitory effect on the Ca(2+)-stimulated adenosine triphosphatase activity of desensitized actomyosin are two properties of different stability to preparative procedures and tryptic digestion. This suggests that the relaxing protein system of muscle may contain another as yet uncharacterized component.

摘要

本文描述了一种从天然肌动球蛋白和肌原纤维的低离子强度提取物中制备不含原肌球蛋白的肌钙蛋白复合物的方法，该方法包括等电沉淀和在SE-葡聚糖凝胶（磺乙基-葡聚糖凝胶）上进行色谱分离。2. 纯化的肌钙蛋白复合物需要原肌球蛋白来抑制Mg(2+)刺激的腺苷三磷酸酶活性以及在乙二氧基双（乙胺）四乙酸存在下脱敏肌动球蛋白的超沉淀。肌钙蛋白复合物“分子量”的上限为35000，这是根据使已知浓度的脱敏肌动球蛋白的Mg(2+)刺激的腺苷三磷酸酶活性达到最大抑制的50%所需的量得出的。3. 在解离试剂存在下，肌钙蛋白复合物可解离为抑制因子和Ca(2+)敏感因子，它们可在SE-葡聚糖凝胶上分别分离。抑制因子可独立于介质中游离Ca(2+)的浓度抑制Mg(2+)刺激的腺苷三磷酸酶活性和脱敏肌动球蛋白的超沉淀。4. Ca(2+)敏感因子在乙二氧基双（乙胺）四乙酸存在下在聚丙烯酰胺凝胶上改变其电泳迁移率。它在低离子强度下与抑制因子形成复合物，并且将抑制因子与Ca(2+)敏感因子按约3:2的比例混合时，可恢复肌钙蛋白复合物的原始生物活性。5. 有证据表明，原肌球蛋白制剂恢复肌钙蛋白复合物松弛蛋白系统活性的能力及其对脱敏肌动球蛋白的Ca(2+)刺激的腺苷三磷酸酶活性的抑制作用是对制备程序和胰蛋白酶消化具有不同稳定性的两种特性。这表明肌肉的松弛蛋白系统可能包含另一种尚未鉴定的成分。