title: Stabilization of porcine spleen cathepsin A with chaotropic ions and its destabilization with thiols at intralysosomal pH.
abstract: 1. A correct assay for cathepsin A was developed by adding 0.1 M NaNO3 as an enzyme stabilizer to the assay system. 2. Cathepsin A was purified homogeneously from porcine spleen by DE 52 column, Sephadex G-150 column and Try-Phe-CH-Sepharose column chromatography. 3. The optimum pH of the cathepsin A activity was 4.9, which is near the value of the intralysosomal pH. 4. Chaotropic agents exerted stabilizing effects on the purified cathepsin A activity at pH 5.0, with sodium nitrate being the most effective among the agents tested. 5. Cathepsin A was inactivated rapidly and irreversibly by thiols.
authors.affiliation: Department of Applied Biological Science, College of Agriculture and Veterinary Medicine, Nihon University, Kanagawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: K
authors.initials: K
authors.lastname: Maruyama
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002268:Carboxypeptidases / Q000737:chemistry* / Q000302:isolation & purification; D043402:Cathepsin A; D002403:Cathepsins / Q000737:chemistry* / Q000302:isolation & purification; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007477:Ions; D008247:Lysosomes / Q000201:enzymology; D013154:Spleen / Q000201:enzymology*; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds; D013552:Swine
chemical_list: D007202:Indicators and Reagents; D007477:Ions; D013438:Sulfhydryl Compounds; D002268:Carboxypeptidases; D002403:Cathepsins; D043402:Cathepsin A