title: Isolation and purification of normal and malignant colonic plasma membranes.
abstract: Plasma membrane fractions from normal colon cells and a transplantable colon adenocarcinoma were isolated and purified by differential and zonal density centrifugation. Enrichment of normal and adenocarcinoma plasma membranes was found in zonal fractions I and II (ZI and ZII) following centrifugation in an 18--50% sucrose gradient. The distribution of various marker enzymes in normal colon preparations suggested an apical origin for the membranes obtained in zonal fraction I while zonal fraction II appeared to contain basal-lateral membrane fragments. Enzymatic analysis of the plasma membrane derived from the colon tumor indicated that these fractions possess a more uniform distribution of Na-K+ ATPase perhaps reflecting a dedifferentiated state. The plasma membrane fractions isolated should prove useful for investigation of transport and other properties of vesicles derived from malignant and normal colon cells.
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000648:ultrastructure; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology; D003106:Colon / Q000201:enzymology; D003110:Colonic Neoplasms / Q000201:enzymology / Q000648:ultrastructure; D005260:Female; D009374:Neoplasms, Experimental / Q000201:enzymology / Q000648:ultrastructure; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism
chemical_list: D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium