Selve N, Wegner A
Institut für Physiologische Chemie, Ruhr-Universität Bochum, Federal Republic of Germany.
Eur J Biochem. 1987 Oct 1;168(1):111-5. doi: 10.1111/j.1432-1033.1987.tb13394.x.
The assembly of gelsolin with actin was followed by the increase of the fluorescence intensity of a fluorescence label bound to actin. The time course of the formation of the gelsolin-actin complex in the presence of micromolar [Ca2+] could be quantitatively interpreted by a model in which one actin molecule binds slowly to gelsolin in a rate-determining step and subsequently a second actin molecule is bound at least 40 times more rapidly. The rate of binding of the first actin molecule to gelsolin was found to be remarkably slow and to depend on the pH. The rate constants of formation of the gelsolin-actin complex range from 1.5 X 10(4) M-1 s-1 at pH 8 to 7 X 10(4) M-1 s-1 at pH 6.
凝溶胶蛋白与肌动蛋白的组装过程通过与肌动蛋白结合的荧光标记物荧光强度的增加来跟踪。在微摩尔浓度的[Ca2+]存在下，凝溶胶蛋白-肌动蛋白复合物形成的时间进程可以用一个模型进行定量解释，该模型中一个肌动蛋白分子在限速步骤中缓慢结合到凝溶胶蛋白上，随后第二个肌动蛋白分子的结合速度至少快40倍。发现第一个肌动蛋白分子与凝溶胶蛋白的结合速度非常慢且依赖于pH值。凝溶胶蛋白-肌动蛋白复合物形成的速率常数范围从pH 8时的1.5×10(4) M-1 s-1到pH 6时的7×10(4) M-1 s-1。
