Strömqvist M, Backman L, Shanbhag V P
J Muscle Res Cell Motil. 1984 Aug;5(4):443-55. doi: 10.1007/BF00818262.
The effect of polyethylene glycol on the kinetics of actin polymerization was determined by monitoring the enhancement in the fluorescence of pyrenyl-labelled actin. The polymerization of actin at 15 mM KCl was in addition followed by viscometry and light scattering. All three methods showed that the overall rate of polymerization of actin increased 3-4-fold when the concentration of polyethylene glycol was increased from 0 to 6% (ww-1). A further increase in polyethylene glycol concentration to 10% (ww-1) caused a relatively small contribution to the increase in the rate of polymerization. The enhancement of the overall rate of polymerization by polyethylene glycol was also reflected in a significant decrease in the lag time observed when the time course of polymerization was followed by viscometry and light scattering. The steady-state value of fluorescence enhancement and critical concentration of actin were also influenced by polyethylene glycol and the results showed that the extent of polymerization was increased by an increase in the concentration of polyethylene glycol in solution. The effect of polyethylene glycol on both rate and extent of polymerization persisted at physiological salt concentration (150 mM KCl, 2 mM MgCl2). Since the rate of elongation was affected only to a small extent by polyethylene glycol, we propose that its main effect is on nucleation.
通过监测芘标记肌动蛋白荧光的增强来确定聚乙二醇对肌动蛋白聚合动力学的影响。此外，在15 mM KCl条件下，通过粘度测定法和光散射法跟踪肌动蛋白的聚合过程。所有这三种方法均表明，当聚乙二醇浓度从0增加到6%（重量/重量）时，肌动蛋白的总体聚合速率提高了3至4倍。聚乙二醇浓度进一步增加至10%（重量/重量）时，对聚合速率增加的贡献相对较小。聚乙二醇对聚合总体速率的增强作用还反映在通过粘度测定法和光散射法跟踪聚合时间过程时观察到的滞后时间显著缩短。荧光增强的稳态值和肌动蛋白的临界浓度也受聚乙二醇影响，结果表明溶液中聚乙二醇浓度的增加会使聚合程度提高。在生理盐浓度（150 mM KCl，2 mM MgCl2）下，聚乙二醇对聚合速率和聚合程度的影响依然存在。由于聚乙二醇对伸长速率的影响很小，我们认为其主要作用是对成核过程的影响。
