title: Purification and characterization of a calpain activator from human platelets.
abstract: A calpain (Ca(2+)-activated neutral protease) activator was purified from human platelets by ammonium sulfate fractionation, gel-filtration, ion-exchange chromatography, followed by heat-treatment. The purified calpain activator with a Mr of 47.5 kDa was a heat-stable protein as demonstrated in other cells. The calpain activator did not change the Ca2+ sensitivity of calpain but activated calpain activity about 2-fold. This calpain activator may play an important role in the activation of the protease system leading to the Ca(2+)-mediated physiological process of platelets.
authors.affiliation: Dept. of Surgery II, Osaka University Medical School, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Shiba
authors.forename: H
authors.initials: H
authors.lastname: Ariyoshi
authors.forename: Y
authors.initials: Y
authors.lastname: Yano
authors.forename: T
authors.initials: T
authors.lastname: Kawasaki
authors.forename: M
authors.initials: M
authors.lastname: Sakon
authors.forename: J
authors.initials: J
authors.lastname: Kambayashi
authors.forename: T
authors.initials: T
authors.lastname: Mori
mesh_terms: D001685:Biological Factors / Q000097:blood / Q000302:isolation & purification; D001792:Blood Platelets / Q000378:metabolism*; D002154:Calpain / Q000097:blood* / Q000302:isolation & purification; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006801:Humans; D007700:Kinetics; D008970:Molecular Weight
chemical_list: D001685:Biological Factors; D002154:Calpain