桥粒蛋白生化免疫特性研究

Biochemical and Immunological Characterization of Desmosomal Proteins

桥粒在含高浓度脲(0.5mol/L)的变性剂中(100℃)作用30分钟即能完全溶解.经SDS-PAGE分离获得7条高分子量(>67kd)蛋白带和一些小分子量角蛋白。这7条高分子量蛋白带是桥粒的特异组成蛋白,即桥粒蛋白Ⅰ和Ⅱ(Desmoplakin Ⅰ和Ⅱ),多肽3、4a、4b、5、6,它们的分子量分别为250kd和215kd、165kd、130kd、115kd、83kd及75kd.用制备电泳法1次可提取Desmoplakin Ⅰ 2～2.5mg,纯度达93.1％.等电聚焦电泳测定其等电点为6.8～7.2。氨基酸组成分析甘氨酸含量很高,免疫印迹表明能被Desmoplakin Ⅰ McAb识别.

Desmosmoes were dissolvedby incubation at 100℃ for 30 minutes inlysis buffer containing 9. 5M urea. SDS-PAGE revealed seven high molecular weight(>67kd) for bands and some keratins. Sevenof these were considered to be major bands.Bands 1 and 2 with Mr values of 250kd and215kd,called desmoplakins Ⅰ and Ⅱ. Poly-peptide bands 3,4a 4b,5 and 6 had Mr val-ues of 165kd,130kd, 115kd,83kd and 75kd,respectively. 2-2. 5mg of Desmoplakin I wasobtained by a preparative electrophoresis;the purity reached 93.1%. The IsoelectricpH range was between 6. 8 and 7. 2,and theamino acid compositions displayed a rela-tively high content of glycine. It wasfound that McAb Desmoplakin I recognizedspecifically the 250kd antigenic band byimmunoblotting.