title: Purification and biochemical characterization of an extracellular serine peptidase from Aspergillus terreus.
abstract: Peptidases are important because they play a central role in pharmaceutical, food, environmental, and other industrial processes. A serine peptidase from Aspergillus terreus was isolated after two chromatography steps that showed a yield of 15.5%. Its molecular mass was determined to be 43 kD, by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). This peptidase was active between pH 5.0 to 8.0 and had maximum activity at pH 7.0, at 45°C. When exposited with 1 M of urea, the enzyme maintained 100% activity and used azocasein as substrate. The N-terminal (first 15 residues) showed 33% identity with the serine peptidase of Aspergillus clavatus ES1. The kinetics assays showed that subsite S2 did not bind polar basic amino acids (His and Arg) nonpolar acidic amino acids (Asp and Glu). The subsite S1 showed higher catalytic efficiency than the S2 and S3 subsites.
authors.affiliation: a Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto , University of São Paulo , Ribeirão Preto , Brazil.
authors.forename: Rafael Tage
authors.initials: RT
authors.lastname: Biaggio
authors.affiliation: b Institute of Biosciences, Letters and Exact Sciences , Universidade Estadual Paulista , São José do Rio Preto , Brazil.
authors.forename: Ronivaldo Rodrigues da
authors.initials: RR
authors.lastname: Silva
authors.affiliation: a Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto , University of São Paulo , Ribeirão Preto , Brazil.
authors.forename: Nathalia Gonsales da
authors.initials: NG
authors.lastname: Rosa
authors.affiliation: c Faculty of Biological and Environmental Sciences , Federal University of Grande Dourados , Dourados , Brazil.
authors.forename: Rodrigo Simões Ribeiro
authors.initials: RS
authors.lastname: Leite
authors.affiliation: d Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto , University of São Paulo , Ribeirão Preto , Brazil.
authors.forename: Eliane Candiani
authors.initials: EC
authors.lastname: Arantes
authors.affiliation: e Faculty of Pharmacy , University Center of Educational Foundation of Barretos , Barretos , Brazil.
authors.forename: Tatiana Pereira de Freitas
authors.initials: TP
authors.lastname: Cabral
authors.affiliation: f Department of Biophysics, Paulista School of Medicine , Federal University of São Paulo , São Paulo , Brazil.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Juliano
authors.affiliation: f Department of Biophysics, Paulista School of Medicine , Federal University of São Paulo , São Paulo , Brazil.
authors.forename: Luiz
authors.initials: L
authors.lastname: Juliano
authors.affiliation: a Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto , University of São Paulo , Ribeirão Preto , Brazil.
authors.forename: Hamilton
authors.initials: H
authors.lastname: Cabral
mesh_terms: D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D057057:Serine Proteases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature
chemical_list: D057057:Serine Proteases
keywords: Aspergillus; N-terminal sequence; enzyme kinetics; filamentous fungi; protease; protein