title: Purification and some properties of cathepsin A of small molecular size from pig kidney.
abstract: Cathepsin A [EC 3.4.2.-] of small molecular size (cathepsin A, S) has been purified about 800-fold from pig kidney by procedures including chromatographies on DEAE-Sephadex, SP-Sephadex, and Sephadex G-150. 1. The homogeneity of the purified enzyme was proved by ultracentrifugation and polyacrylamide gel electrophoresis. The molecular weight (100,000) and isoelectric point (pI=5.0) were estimated. 2. The enzyme was remarkably stabilized by sucrose and KCl, and was most stable at pH 5-5.5 in the presence of both stabilizers. The enzyme had not only peptidase activity but also esterase and amidase activity; it was optimally active at pH 5.2 for peptide hydrolysis and at pH 8 for the hydrolysis of esters and amides. 3. Diisopropyl fluorophosphate and iodoacetamide completely inhibited these three activities. 4. The enzyme hydrolyzed various benzoyl- and benzyloxycarbonyl-dipeptides with neutral, acidic, and basic amino acids, and proline in the C-terminal position. The carboxypeptidase nature of the enzyme was proved by its action on an oligopeptide. 5. Several enzymatic properties of cathepsin A, S were almost the same as thoas of cathepsin A of large molecular size (cathepsin A, L) and the crude homogenate.
mesh_terms: D000818:Animals; D001565:Benzoates; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D002848:Chromatography, DEAE-Cellulose; D004151:Dipeptides; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007460:Iodoacetamide; D007531:Isoflurophate; D007668:Kidney / Q000201:enzymology*; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism; D011189:Potassium Chloride; D013395:Sucrose; D013552:Swine; D014461:Ultracentrifugation
chemical_list: D001565:Benzoates; D004151:Dipeptides; D010455:Peptides; D007531:Isoflurophate; D013395:Sucrose; D011189:Potassium Chloride; D002403:Cathepsins; D007460:Iodoacetamide