Strzelecka-Gołaszewska H, Zmorzyński S, Mossakowska M
Biochim Biophys Acta. 1985 Mar 22;828(1):13-21. doi: 10.1016/0167-4838(85)90003-2.
Crude actin extracts from acetone-dried powder of the muscle layer of bovine aorta contain an actin-modulating protein which promotes nucleation of actin monomers and decreases the average length of actin filaments in a Ca2+-dependent manner. This observation has allowed the development of an improved purification procedure for aorta actin which increases the yield 2- to 3-times. The actin obtained with this procedure consists of 77% alpha- and 23% gamma-isoelectric species. Pure aorta actin is indistinguishable from actins from skeletal, cardiac and chicken-gizzard smooth muscle in its polymerization rate, critical concentration, and reduced viscosity when polymerized with KCl at 25 degrees C. It differs from sarcomeric actins, but not from chicken-gizzard smooth muscle actin, in the temperature dependence of polymerization equilibria in KCl. This difference correlates with the amino acid replacements Val-17----Cys-17 and Thr-89----Ser-89, supporting a conclusion drawn from other studies that the N-terminal portion of actin polypeptide chain contains sites important for polymerization.
从牛主动脉肌层的丙酮干粉中提取的粗肌动蛋白提取物含有一种肌动蛋白调节蛋白，该蛋白以钙离子依赖的方式促进肌动蛋白单体的成核作用，并缩短肌动蛋白丝的平均长度。这一发现使得改进后的牛主动脉肌动蛋白纯化方法得以开发，该方法可使产量提高2至3倍。通过该方法获得的肌动蛋白由77%的α-等电点物种和23%的γ-等电点物种组成。纯牛主动脉肌动蛋白在聚合速率、临界浓度以及在25℃下与氯化钾聚合时的比浓粘度方面，与骨骼肌、心肌和鸡胗平滑肌中的肌动蛋白没有区别。在氯化钾中，其聚合平衡的温度依赖性与肌节肌动蛋白不同，但与鸡胗平滑肌肌动蛋白相同。这种差异与氨基酸替换Val-17→Cys-17和Thr-89→Ser-89相关，支持了其他研究得出的结论，即肌动蛋白多肽链的N端部分含有对聚合作用重要的位点。
