Jen C J, McIntire L V
Biochim Biophys Acta. 1984 Oct 16;801(3):410-5. doi: 10.1016/0304-4165(84)90146-6.
The kinetics of the gelation process that occurs upon warming cold platelet extracts were studied using a sensitive rheometer. At micromolar or less free Ca2+ concentrations and in the presence of 1 mM ATP, the gel rigidity curves showed several peaks, indicating that platelet extract proteins went through network assembling/disassembling cycles during gelation. The gelation kinetics were accelerated by increasing the free Ca2+ concentration up to about 2 microM. At 4-15 microM free Ca2+, the gelation cycles were completely abolished except for the first peak. The gelation process became one of monotonically increasing elastic modulus at millimolar free Ca2+ concentrations. Trifluoperazine (50 microM), a calmodulin inhibitor, did not affect gelation at micromolar free Ca2+ concentrations. Except for the first gelation step, which was completed within 5 min after warming, the rest of the gelation process was found to be affected by K+, ATP, cytochalasin E and colchicine. K+ at concentrations higher than 10 mM retarded the gelation kinetics. Extracts prepared with low (0.1 mM) ATP content showed impaired gelation, and this was partially reversed by adding 1 mM ATP, but not 1 mM adenylylimidodiphosphate (p[NH]ppA). Both cytochalasin E (1 microM) and colchicine (1 mM) interfered with the gelation process.
使用灵敏的流变仪研究了冷血小板提取物升温时发生的凝胶化过程的动力学。在微摩尔或更低的游离Ca2+浓度以及存在1 mM ATP的情况下，凝胶刚性曲线显示出几个峰值，表明血小板提取物蛋白在凝胶化过程中经历了网络组装/拆卸循环。通过将游离Ca2+浓度增加至约2 microM，凝胶化动力学加速。在4 - 15 microM游离Ca2+时，除第一个峰值外，凝胶化循环完全消失。在毫摩尔游离Ca2+浓度下，凝胶化过程变成了弹性模量单调增加的过程之一。钙调蛋白抑制剂三氟拉嗪（50 microM）在微摩尔游离Ca2+浓度下不影响凝胶化。除了升温后5分钟内完成的第一个凝胶化步骤外，发现凝胶化过程的其余部分受K+、ATP、细胞松弛素E和秋水仙碱的影响。浓度高于10 mM的K+会延迟凝胶化动力学。用低（0.1 mM）ATP含量制备的提取物显示凝胶化受损，通过添加1 mM ATP可部分逆转，但添加1 mM腺苷酰亚胺二磷酸（p[NH]ppA）则不能。细胞松弛素E（1 microM）和秋水仙碱（1 mM）均干扰凝胶化过程。
