A rapid and simplified method for the preparation of lysosomal membranes from rat liver

A rapid and simplified method for the preparation of lysosomal membranes from rat livers was developed. Enzymic characterization showed that the lysosomal membrane preparation isolated by this procedure was almost free from mitochondria, peroxisomes, and endoplasmic reticulum. Acid phosphatase was used as a marker enzyme for lysosomal membrane, because about 40% of the total acid phosphatase activity in the lysosomes was associated with the membranes. With this method, the yield of the purified membrane was 115 micrograms/g wet weight of liver and the relative specific activity of acid phosphatase in the purified membrane was 105-110. On SDS-polyacrylamide gel electrophoretic analysis, the purified membrane revealed glycoprotein bands in the region of M.W. between 60,000 and 110,000, which were characteristic of the tritosomal membrane. Our lysosomal membrane preparation was compared with lysosomal membranes prepared from normal rat liver lysosomes isolated by the method of Wattiaux et al. [(1978) J. Cell Biol. 78, 349-368]. Although the specific activity of acid phosphatase in our membrane preparation was higher than that in the membrane prepared by the existing method, the electrophoretic profiles of both membrane preparations were quite similar.