Isolation of skeletal muscle cell membrane and some of its properties

Abstract

A procedure is described for the isolation of empty tubular cell membrane-like structures from rat skeletal muscle. The procedure resulted in a purification of about 140-fold in terms of protein content per tube. The yield was about 20% in terms of total number of tubes recovered. The purest preparations contained about 65% protein, 15% lipid, and 3% carbohydrate on a dry-weight basis. Most of the lipid was phospholipid which became ether-extractable only on acidification. Most of the protein had the composition of collagen. That the membrane structure itself contained a collagen-like protein is suggested by the fact that the membranes were dissolved by collagenase or dilute acetic acid and showed a critical shrinkage temperature at 57–59°. A preliminary survey of enzyme activities found in the membrane fraction is reported. No evidence was obtained for binding of insulin or d -galactose by the purified membrane fraction.