Isolation of skeletal muscle plasmatic membranes as closed vesicles

Ultrasonic treatment of skeletal muscle sarcolemma preparations in 0.25 M sucrose, 0.1 M NaCl, 0.001 M tris-HCl-buffer (pH 7.4) induces formation of closed osmotically active vesicles which may be isolated by centrifugation of a sonicated suspension within the sucrose density gradient. The vesicles retain the enzymic activity peculiar to the initial sarcolemma preparations.