Stournaras C, Drewes G, Blackholm H, Merkler I, Faulstich H
Department of Physiology, Max Planck Institute for Medical Research, Heidelberg, F.R.G.
Biochim Biophys Acta. 1990 Jan 19;1037(1):86-91. doi: 10.1016/0167-4838(90)90105-o.
Rabbit muscle actin reacts with 2,4-dinitrophenylglutathionyldisulfide, forming a mixed disulfide in position 374. the product S-(cysteine-374)glutathionyl actin forms filaments which are easily disrupted under shearing stress. Even weak mechanical strain, as exerted, for example, during capillary viscometry or heating the solution to 37 degrees C, leads to considerable breakage of these filaments. Because of spontaneous repair which consumes ATP, the mechanically broken filaments exhibit an approx. 6-fold enhanced steady-state ATPase activity as compared to normal F-actin. Monomers of glutathionyl actin have a reduced affinity for their bound nucleotide and a slightly increased critical concentration. Disruption of the filaments and enhanced ATPase activity are reversed by the addition of KCl or the mushroom toxin phalloidin. By the large stabilizing effects of KCl and phalloidin on glutathionyl actin filaments we propose glutathionyl actin as a tool for detecting filament-stabilizing agents and for studying the different mechanisms of filament stabilization.
兔肌肉肌动蛋白与2,4 - 二硝基苯基谷胱甘肽二硫化物反应，在第374位形成混合二硫化物。产物S -（半胱氨酸-374）谷胱甘肽基肌动蛋白形成的细丝在剪切应力下很容易被破坏。即使是微弱的机械应变，例如在毛细管粘度测定过程中施加的应变或将溶液加热到37摄氏度时产生的应变，也会导致这些细丝大量断裂。由于消耗ATP的自发修复作用，与正常F - 肌动蛋白相比，机械断裂的细丝表现出约6倍增强的稳态ATP酶活性。谷胱甘肽基肌动蛋白单体对其结合核苷酸的亲和力降低，临界浓度略有增加。通过添加KCl或蘑菇毒素鬼笔环肽，细丝的破坏和增强的ATP酶活性会逆转。基于KCl和鬼笔环肽对谷胱甘肽基肌动蛋白细丝的巨大稳定作用，我们提出谷胱甘肽基肌动蛋白可作为检测细丝稳定剂和研究细丝稳定不同机制的工具。
