Nishida E, Muneyuki E, Maekawa S, Ohta Y, Sakai H
Biochemistry. 1985 Nov 5;24(23):6624-30. doi: 10.1021/bi00344a049.
An Mr 19 000 protein (destrin) that has the ability to rapidly depolymerize F-actin in a stoichiometric manner was purified from porcine kidney by sequential chromatography on DNase I-agarose, hydroxyapatite, and Sephadex G-75. Its actin-depolymerizing activity is reversibly controlled by changes in KCl concentration but is insensitive to Ca2+ concentration. The rate of depolymerization of F-actin by destrin is much faster than that of spontaneous depolymerization induced by dilution and is not markedly decreased by the addition of end-blocking reagents such as cytochalasin B. These results suggest that destrin depolymerizes F-actin by interacting directly with F-actin protomers. Binding of muscle tropomyosin to F-actin slows down the rate of destrin-induced depolymerization of F-actin by about 30-fold. The data suggest that the destrin-induced depolymerization occurs from the ends of F-actin when F-actin is complexed with tropomyosin, but it takes place from the entire length of F-actin in the absence of tropomyosin.
一种分子量为19000的蛋白质（肌动蛋白解聚因子），它能够以化学计量的方式快速解聚F-肌动蛋白，通过在脱氧核糖核酸酶I-琼脂糖、羟基磷灰石和葡聚糖凝胶G-75上的连续层析从猪肾中纯化得到。其肌动蛋白解聚活性可通过氯化钾浓度的变化进行可逆控制，但对钙离子浓度不敏感。肌动蛋白解聚因子使F-肌动蛋白解聚的速度比稀释诱导的自发解聚速度快得多，并且添加诸如细胞松弛素B等封端试剂后也不会明显降低。这些结果表明，肌动蛋白解聚因子通过直接与F-肌动蛋白原纤维相互作用来解聚F-肌动蛋白。肌肉原肌球蛋白与F-肌动蛋白的结合使肌动蛋白解聚因子诱导的F-肌动蛋白解聚速度减慢约30倍。数据表明，当F-肌动蛋白与原肌球蛋白结合时，肌动蛋白解聚因子诱导的解聚发生在F-肌动蛋白的末端，但在没有原肌球蛋白的情况下，解聚发生在F-肌动蛋白的全长。
