Liou R S, Anderson S
Biochemistry. 1980 Jun 10;19(12):2684-8. doi: 10.1021/bi00553a022.
Striking effects of F-actin and the reconstituted thin filament of muscle on the catalytic activity of rabbit muscle phosphofructokinase are demonstrated through direct measurements of enzymatic activity by using the pH stat. The addition of F-actin to solutions of phosphofructokinase at low ionic strength (10 mM KCl and 5 mM MgCl2) partially reverses the inhibition of the enzyme seen at high ATP concentrations and increases the apparent affinity of the enzyme for fructose 6-phosphate with slight effect on Vmax. F-Actin augments the activation of the enzyme obtained with AMP and partially counters the inhibition obtained with citrate. The maximum effect in the reversal of ATP inhibition is about the same for combinations of either F-actin or the thin filament with AMP as it is for AMP alone. In general, the effect of F-actin on the catalytic activity of phosphofructokinase is larger than that of the thin filament. The activation of phosphofructokinase by F-actin persists at physiological ionic strength.
通过使用pH计直接测量酶活性，证明了F-肌动蛋白和重组的肌肉细肌丝对兔肌肉磷酸果糖激酶催化活性具有显著影响。在低离子强度（10 mM KCl和5 mM MgCl2）下，向磷酸果糖激酶溶液中添加F-肌动蛋白可部分逆转在高ATP浓度下观察到的酶抑制作用，并增加酶对6-磷酸果糖的表观亲和力，对Vmax影响轻微。F-肌动蛋白增强了用AMP获得的酶激活作用，并部分抵消了用柠檬酸盐获得的抑制作用。对于F-肌动蛋白或细肌丝与AMP的组合，逆转ATP抑制的最大效果与单独使用AMP时大致相同。一般来说，F-肌动蛋白对磷酸果糖激酶催化活性的影响大于细肌丝。F-肌动蛋白对磷酸果糖激酶的激活作用在生理离子强度下持续存在。
