title: Membrane proteinases from normal and neoplastic tissues in man and the rat.
abstract: Plasma membranes were purified from rat liver, muscle and sarcoma tissues and from human liver and hepatoma tissues. The plasma membranes all contained DFP-sensitive, neutral proteolytic activity. Plasma membranes from all normal tissues contained a single DFP-binding protein of apparent molecular weight 68,000. Only the plasma membranes from tumour tissue contained a plasminogen activator; the DFP-binding proteins from these membranes were more diverse than those from the normal samples. The rat liver plasma membrane proteinase was purified. It was a labile enzyme sensitive to inhibition by DFP and by calcium ions, and with a broad substrate specificity. A similar protein was the sole DFP-binding protein in rat liver microsomes. This and the properties of the enzyme suggested a possible role in the processing and secretion of newly-synthesized protein.
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007531:Isoflurophate / Q000494:pharmacology; D008113:Liver Neoplasms / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology*; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000302:isolation & purification*; D051381:Rats; D012513:Sarcoma, Experimental / Q000201:enzymology*
chemical_list: D007531:Isoflurophate; D010447:Peptide Hydrolases