Mockrin S C, Korn E D
Biochemistry. 1980 Nov 11;19(23):5359-62. doi: 10.1021/bi00564a033.
A sevenfold molar excess of Acanthamoeba profilin, a 12 000-dalton protein that inhibits actin polymerization, increases the rate of exchange of ATP bound to G-actin with ATP in solution about 17-fold, i.e., from 7.7 x 10(-4) to 1.3 x 10(-2) S-1, at 25 degrees C, 0.033 mM Ca2+, and 0.1 mM ATP, pH 7.5. Detailed analysis of the equilibrium isotope-exchange data shows that profilin and actin form a 1:1 complex with KD = 4.7 x 10(-5) M and that the binding of profilin to actin is rapid and reversible. The actin-profilin complex binds 1 mol of ATP/mol, as does G-actin. Profilin does not interact with ATP or Ca2+.
棘阿米巴肌动蛋白单体结合蛋白（一种分子量为12000道尔顿、抑制肌动蛋白聚合的蛋白质）的七倍摩尔过量，在25℃、0.033 mM钙离子、0.1 mM三磷酸腺苷（ATP）、pH 7.5的条件下，使结合在球状肌动蛋白（G-肌动蛋白）上的ATP与溶液中的ATP之间的交换速率提高了约17倍，即从7.7×10⁻⁴变为1.3×10⁻² S⁻¹。对平衡同位素交换数据的详细分析表明，肌动蛋白单体结合蛋白与肌动蛋白形成1:1复合物，解离常数KD = 4.7×10⁻⁵ M，且肌动蛋白单体结合蛋白与肌动蛋白的结合迅速且可逆。肌动蛋白 - 肌动蛋白单体结合蛋白复合物与G-肌动蛋白一样，每摩尔结合1摩尔ATP。肌动蛋白单体结合蛋白不与ATP或钙离子相互作用。
