Lipid components of sarcotubular membranes

Abstract

Abstract The lipid composition of a highly purified preparation of rat skeletal muscle sarcoplasmic reticulum was studied. These membranes contain per mg of protein 0.50 ± 0.02 μmoles of phosphatidylcholine, 0.13 ± 0.02 μmoles of phosphatidylethanolamine and 0.07 ± 0.02 μmoles ofphosphatidylinositol. These three components account for 97.3% of total lipid phosphorus. Unlike other mammalian membranes so far studied, this preparation contains neither sphingomyelin nor phosphatidylserine. Neural lipids were also measured and it is concluded that neither cholesterol nor other neutral lipids are components of the membranes studied. The results of this study indicate therefore that the lipid profile of sarcotubular membranes is relatively simple compared with most other membranes.