Abstract
Sarcoplasmic reticulum subfractions were isolated from rabbit sarcoplasmic reticulum vesicles using ultracentrifugation in a continuous sucrose gradient (12.5% 50%) after French pressure treatment. And proteins in sarcoplasmic reticulum were detected by SDS-polyacrylamide gel electrophoresis and glycoproteins were identified through the reaction with 1251-concanavalin A.The electrophoresis showed that sarcoplasmic reticulum contained predominantly $Ca^2$+-AThase and calsequestrin along with high affinity calcium binding protein, intrinsic glycoprotein 160 Kd, 94 Kd, 80 Kd, 38 Kd, 34 Kd and 24 Kd proteins. Among these, the protein of about 80 Kd which has been known as one of heat shock proteins was especially enriched in the terminal cistemae of sarcoplasmic reticulum. Meanwhile, autoradiogram of 125 I-concanavalin A bound to the stained gels showed the distribution of glycoproteins which included 160 Kd glycoprotein, 94 Kd glycoprotein, calsequestrin and intrinsic glycoprotein Among these, the protein of about 160 Kd was especially enriched in longitudial sarcoplasmic reticulum and T-tubule, and the protein of about 94 Kd which has been known as one of glucose-regulated proteins was also enriched in T-tubule and sharply reduced in terminal cistemae.
토끼의 골격근에서 근소포체를 순수 분리하여 SDS-polyacrylamide gel전기영동법과 125 I-concanavalin A표지법으로 단백질과 당단백질의 조성을 조사하였다. 전기영동사에 나타난 대표적인 단백질은 $Ca^2$+-AThase, 80 Kd protein,calsequestrin,high affinity calcium binding protein, intrinsic glycoprotein이었으며, 160 Kd protein, 94 Kd protein,38 Kd protein, 34 Kd protein,24 Kd proteins도 존재하였다.특히, 막성계에 있는 heak protein으로 알려져 있는 80 Kd protein은 본 연구를 통해 주로 근소포체의 terminal cisternae에 들어 있음이 확인되었다. 한편 125 I-concanavalin A표지에 의해 전기영동성에 나타난 대표적인 당단백질은 160 Kd glycoprotein, 94 Kd glycoprotein, calsequestrin, intrinsic glycoprotein의 4종이었다. 이 가운데 94 Kd glycoprotein은 94 Kd glucose-regulated protein으로 추정되며, 본 연구를 통해 근소포체에서도 특히 T-tubule에 다량으로 존재함이 밝혀졌다.