Podolsak B
Thromb Haemost. 1977 Jun 30;37(3):396-406.
Analysis of platelet membrane proteins and glycoproteins by SDS polyacrylamide gel electrophoresis was carried out before and after treatment with thrombin. Extended incubation with thrombin (in the presence of EDTA or adenosine, which inhibit aggregation) produced extensive changes in the bands observed. With incubation times of a few minutes however, the changes were restricted to a glycopeptide, GP IV (approx. 90,000 Daltons) and one or two polypeptides of low molecular weight, in particular polypeptide 16 (approx. 23,000 Daltons). At 0--3 degrees C only polypeptide 16 was still hydrolyzed. Chymotrypsin, which does not activate platelets, attacked glycopeptides I, II, III but no changes were apparent in GP IV and polypeptide 16. When chymotrypsin-treated platelets were further incubated with thrombin, only GP IV and one to two low molecular weight polypeptides, especially polypeptide 16, were affected. As polypeptide 16 appears to be an integral membrane component it is possible that it, either by itself or in combination with GP IV, represents the primary thrombin substrate involved in platelet activation. Aggregated IgG, which also activates platelets, does not modify the membrane glycoproteins but does change the low molecular weight region in particular band 16.
在用凝血酶处理前后，通过SDS聚丙烯酰胺凝胶电泳对血小板膜蛋白和糖蛋白进行了分析。在凝血酶长时间孵育（存在抑制聚集的EDTA或腺苷）后，观察到的条带发生了广泛变化。然而，孵育几分钟时，变化仅限于一种糖肽GP IV（约90,000道尔顿）和一两种低分子量多肽，特别是多肽16（约23,000道尔顿）。在0 - 3摄氏度时，只有多肽16仍被水解。不激活血小板的胰凝乳蛋白酶作用于糖肽I、II、III，但GP IV和多肽16没有明显变化。当用胰凝乳蛋白酶处理过的血小板再与凝血酶孵育时，只有GP IV和一两种低分子量多肽，特别是多肽16受到影响。由于多肽16似乎是一种完整的膜成分，因此有可能它本身或与GP IV结合，代表了参与血小板激活的主要凝血酶底物。同样能激活血小板的聚集IgG不会改变膜糖蛋白，但会改变特别是条带16的低分子量区域。
