Gard D L, Lazarides E
J Cell Biol. 1979 May;81(2):336-47. doi: 10.1083/jcb.81.2.336.
Guinea pig liver transglutaminase has been found to catalyze the covalent incorporation of dansylcadaverine into chicken skeletal muscle myofibril proteins. Epifluorescence microscopy reveals that the incorporated dansylcadaverine is specifically localized at or near the myofibril Z line. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) indicates that actin constitutes a major fraction of the labeled material; the Z-line proteins alpha-actinin and desmin also show significant labeling, as well as tropomyosin, several additional unidentified proteins, and material with an extremely high molecular weight. The Z-line-specific fluorescence can be removed by brief trypsinization, which releases fluorescent alpha-actinin into the supernate. The majority of the fluorescent protein species are resistant to extraction by either 0.6 M KCl or KI. These results, in conjunction with the microscopic localization, suggest that the dansyl-labeled proteins are constituents of the myofibril Z line. A significant amount of fluorescently labeled transglutaminase is also present in labeled myofibrils, which is resistant to extraction with either 0.6 M KCl or KI. This result indicates a strong, noncovalent interaction between the transglutaminase molecule and the myofibril Z line.
已发现豚鼠肝脏转谷氨酰胺酶可催化丹磺酰尸胺共价掺入鸡骨骼肌肌原纤维蛋白中。落射荧光显微镜检查显示，掺入的丹磺酰尸胺特异性定位于肌原纤维Z线处或其附近。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）表明，肌动蛋白是标记物质的主要成分；Z线蛋白α-辅肌动蛋白和结蛋白也显示出显著标记，原肌球蛋白、其他几种未鉴定的蛋白质以及分子量极高的物质也是如此。短暂用胰蛋白酶处理可去除Z线特异性荧光，这会将荧光α-辅肌动蛋白释放到上清液中。大多数荧光蛋白种类对0.6M氯化钾或碘化钾的提取具有抗性。这些结果，结合显微镜定位，表明丹磺酰标记的蛋白质是肌原纤维Z线的组成成分。标记的肌原纤维中也存在大量荧光标记的转谷氨酰胺酶，其对0.6M氯化钾或碘化钾的提取具有抗性。这一结果表明转谷氨酰胺酶分子与肌原纤维Z线之间存在强烈的非共价相互作用。
