title: Isolation and characterization of the plasma membrane from Yoshida hepatoma cells.
abstract: Plasma membranes isolated from Yoshida ascites hepatoma AH-130 by a modification of the method of T.K. Ray (Biochim. Biophys. Acta 196:1, 1970), were subfractionated into three fractions having densities (d) 1.12, 1.14 and 1.16 by discontinuous sucrose density-gradient. Membrane subfractions were characterized by electron-microscopy, by assay of marker enzymes and by lipid composition. All subfractions appeared to be essentially free from whole mitochondria, lysosomes and nuclei. Subfraction d 1.16 had the highest 5'-nucleotidase, Mg++-ATPase and (Na+ +K+)-ATPase activities; cytochrome c oxidase was undetectable in any fraction and glucose-6-phosphatase was measurable only in fraction d 1.14 and 1.16. Cyclic AMP phosphodiesterase was nearly equally distributed in the fractions. Adenylate cyclase, 5'-nucleotidase and Mg++-ATPase activities of tumor membrane were lower with respect to liver plasma membrane, while cyclic AMP phosphodiesterase and (Na" +K+)-ATPase were found to have similar activities in the two membrane preparations. With respect to liver membrane, hepatoma membrane contained a higher amount of glycolipids and a higher amount of phospholipids accounted for mainly by sphingomyelin, phosphatidylserine and phosphatidic acid. The possible significance of the decrease of adenylate activity in the hepatoma membrane is briefly discussed.
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000032:analysis / Q000473:pathology*; D002458:Cell Fractionation; D002462:Cell Membrane / Q000032:analysis / Q000201:enzymology / Q000648:ultrastructure*; D002499:Centrifugation, Density Gradient; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000032:analysis; D008113:Liver Neoplasms; D008297:Male; D009374:Neoplasms, Experimental / Q000032:analysis / Q000473:pathology; D010743:Phospholipids / Q000032:analysis; D051381:Rats
chemical_list: D008055:Lipids; D010743:Phospholipids