Veksler V I
Biull Vsesoiuznogo Kardiol Nauchn Tsentra AMN SSSR. 1987;10(1):72-5.
The aim of the study was to measure calcium binding by chemically skinned fibers of rat myocardium during force development at different concentrations of free Ca2+. Fiber fascicles were incubated in the solution with EGTA and 1% X-100 triton for 48 hours to achieve the maximal possible withdrawal of the sarcolemma and intracellular membrane structures. Ca2+ binding was determined using two markers. The fibers started developing a considerable isometric force at pCa 6.2-6.0, the maximal force was registered at pCa 5.0-4.8. At pCa 5.0 the fibers bound 3.59 +/- 0.21 nM of Ca/mg of protein, while at pCa greater than 6 less than one third of this amount was bound. When [Ca2+] was increased to over 1 microM the curve of Ca2+ binding became much steeper and coincided with the curve of force development. The results suggest that Ca2+ binding by myofibrils is evidently cooperative and depends on mechanic tension.
该研究的目的是在不同游离Ca2+浓度下，测量大鼠心肌化学去表皮纤维在产生力的过程中的钙结合情况。将纤维束在含有乙二醇双四乙酸（EGTA）和1% Triton X-100的溶液中孵育48小时，以尽可能最大程度地去除肌膜和细胞内膜结构。使用两种标记物测定Ca2+结合情况。纤维在pCa 6.2 - 6.0时开始产生相当大的等长力，最大力在pCa 5.0 - 4.8时记录到。在pCa 5.0时，纤维每毫克蛋白质结合3.59±0.21 nM的Ca，而在pCa大于6时，结合量不到该量的三分之一。当[Ca2+]增加到超过1微摩尔时，Ca2+结合曲线变得陡峭得多，并且与力产生曲线重合。结果表明，肌原纤维的Ca2+结合明显具有协同性，并且取决于机械张力。
