Su J Y, Storey K B
Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada.
Biochem Mol Biol Int. 1995 Apr;35(4):781-91.
The interaction of 6-phosphofructo-1-kinase (PFK) with myofibrils was assessed using the purified proteins from rainbow trout white skeletal muscle. More than 70% of PFK activity was bound at pH values between 6 and 7 but higher pHs dissociated the complex. Increasing salt concentrations also reduced PFK binding, with greater sensitivity to salt at pH 7.0 vs pH 6.6. Substrates and allosteric effectors also reduced enzyme binding to myofibrils; 50% of enzyme was released at 0.23, 0.24, 1.3, and 2.0 mM for fructose 6-phosphate, Mg.ATP, ATP and AMP, respectively. However, the addition of a protein crowding agent, poly(ethylene)glycol, greatly enhanced PFK binding to myofibrils, particularly at high pH (8.0) or high [KCl]. The studies suggest that reversible binding of PFK to myofibrils may be an important factor in the control of anaerobic glycolysis in vivo, especially under the cellular conditions of burst swimming exercise.
使用从虹鳟鱼白色骨骼肌中纯化的蛋白质评估了6-磷酸果糖-1-激酶（PFK）与肌原纤维的相互作用。超过70%的PFK活性在pH值6至7之间结合，但较高的pH值会使复合物解离。增加盐浓度也会降低PFK的结合，在pH 7.0时对盐的敏感性高于pH 6.6。底物和变构效应剂也会降低酶与肌原纤维的结合；对于6-磷酸果糖、Mg·ATP、ATP和AMP，分别在0.23、0.24、1.3和2.0 mM时50%的酶被释放。然而，添加蛋白质拥挤剂聚乙二醇会大大增强PFK与肌原纤维的结合，特别是在高pH值（8.0）或高[KCl]时。这些研究表明，PFK与肌原纤维的可逆结合可能是体内无氧糖酵解控制的一个重要因素，特别是在爆发式游泳运动的细胞条件下。
