title: Identification of the aspartic proteinases from human erythrocyte membranes and gastric mucosa (slow-moving proteinase) as catalytically equivalent to cathepsin E.
abstract: Three aspartic proteinases with similar Mr values (approx. 80,000) but from distinct sources (human gastric mucosa, human erythrocyte membranes and rat spleen) were shown to have immunological cross-reactivity and comparable mobilities when subjected to polyacrylamide-gel electrophoresis under non-denaturing conditions. Kinetic parameters (kcat, Km and Ki) were determined for the interactions of the three enzymes with two synthetic chromogenic substrates and five inhibitors (naturally occurring and synthetic). On this basis it would appear that all of the enzymes should be considered equivalent to cathepsin E. pH-activity measurements indicated that the aspartic proteinase that originated from the erythrocyte membranes retained activity at a higher pH value than either of its readily soluble counterparts.
authors.affiliation: Department of Biochemistry, University College, Cardiff, Wales, U.K.
authors.forename: R A
authors.initials: RA
authors.lastname: Jupp
authors.forename: A D
authors.initials: AD
authors.lastname: Richards
authors.forename: J
authors.initials: J
authors.lastname: Kay
authors.forename: B M
authors.initials: BM
authors.lastname: Dunn
authors.forename: J B
authors.initials: JB
authors.lastname: Wyckoff
authors.forename: I M
authors.initials: IM
authors.lastname: Samloff
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases; D020059:Cathepsin E; D002403:Cathepsins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000097:blood / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005753:Gastric Mucosa / Q000201:enzymology*; D006801:Humans; D006868:Hydrolysis; D009842:Oligopeptides / Q000378:metabolism; D010084:Oxidation-Reduction; D011480:Protease Inhibitors; D051381:Rats
chemical_list: D009842:Oligopeptides; D011480:Protease Inhibitors; C057758:lysyl-prolyl-isoleucyl-glutamyl-phenylalanyl-4-nitrophenylalanyl-arginyl-leucine; D002403:Cathepsins; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; D020059:Cathepsin E