DYSTROPHIN-GLYCOPROTEIN COMPLEX PURIFIED FROM HAMSTER CARDIAC-MUSCLE - COMPARISON OF THE COMPLEXES FROM CARDIAC AND SKELETAL-MUSCLES OF HAMSTER AND RABBIT

The dystrophin-glycoprotetn complex was isolated from hamster Ventricu lar muscle by a method involving homogenization of muscle directly in the presence of 1% digitonin, followed by chromatography on succinylat ed wheat germ agglutinin agarose, Diethyl aminoethyl (DEAE) cellulose, and/or immunoaffinity agarose. Protein yield of the DEAE cellulose-pu rified dystrophin-glycoprotein complex was 120+/-30 (n=3) mu g per 5 g hamster Ventricular muscle, The cardiac dystrophin-glycoprotein compl ex, unlike the skeletal muscle counterpart, could not be solubilized f rom a microsomal fraction with digitonin or some other detergents. By sodium dodecyl sulfate gel electrophoresis, protein composition of the dystrophin-glycoprotein complexes from hamster cardiac muscle was fou nd to be significantly different from that of rabbit skeletal muscle w hich has been extensively studied, This difference mainly arises from the species difference, because in hamster the cardiac and skeletal mu scle complexes exhibited essentially the same protein composition. In rabbit, on the other hand, there are differences between the cardiac a nd skeletal complexes in the relative abundance of 60 and 64 kDa prote ins and in the apparent M(r) of alpha-dystroglycan. We found that the content of the dystrophin-glycoprotein complex, estimated by quantitat ive immunoblot assay, is at least 5 times more abundant in cardiac tha n in skeletal muscle in hamster and rabbit. (C) 1996 Academic Press Li mited