title: Purification and partial characterization of Oenococcus oeni exoprotease.
abstract: The exoprotease from Oenococcus oeni produced in stress conditions was purified to homogeneity in two steps, a 14-fold increase of specific activity and a 44% recovery of proteinase activity. The molecular mass was estimated to be 33.1 kDa by gel filtration and 17 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These results suggest that the enzyme is a dimer consisting of two identical subunits. Optimal conditions for activity on grape juice were 25 degrees C and a pH of 4.5. Incubation at 70 degrees C, 15 min, destroyed proteolytic activity. The SDS-PAGE profile shows that the enzyme was able to degrade the grape juice proteins at a significantly high rate. The activity at low pH and pepstatin A inhibition indicate that this enzyme is an aspartic protease. The protease activity increases at acidic pH suggesting that it could be involved in the wine elaboration.
authors.affiliation: Centro de Referencia para Lactobacilos (CERELA), Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 145, 4000, Tucumán, Argentina.
authors.forename: M E
authors.initials: ME
authors.lastname: Farías
authors.forename: M C
authors.initials: MC
authors.lastname: Manca de Nadra
mesh_terms: D001628:Beverages; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D020689:Exopeptidases / Q000302:isolation & purification* / Q000378:metabolism*; D006095:Gram-Positive Cocci / Q000201:enzymology* / Q000254:growth & development; D007934:Leuconostoc / Q000201:enzymology / Q000254:growth & development; D011480:Protease Inhibitors / Q000494:pharmacology; D019685:Rosales; D014920:Wine / Q000382:microbiology
chemical_list: D011480:Protease Inhibitors; D020689:Exopeptidases