title: Purification and characterization of aminopeptidase (pumAPE) from Ustilago maydis.
abstract: The aminopeptidase pumAPE was purified from the haploid fungus Ustilago maydis FB1 strain. The purification procedure consisted of ammonium sulfate fractionation and three chromatographic steps, which included anion-exchange, hydrophobic interaction, and gel filtration chromatography, resulting in a 23% recovery. The molecular mass of the dimeric enzyme was estimated to be 110 kDa and 58 kDa by gel filtration chromatography and SDS-PAGE, respectively. Enzymatic activity was optimal at pH 7.0 and at 35 degrees C toward Lys-pNA and the pI was determined to be 5.1. The enzyme was inhibited by EDTA-Na2, 1,10- phenanthroline, bestantin, PMSF and several divalent cations (Cu2+, Hg2+ and Zn2+). The aminopeptidase showed a preference for lysine and arginine in the N-position. The K(m) value was 54.4 microM and the Vmax value was 408 micromolmin(-1)mg(-1) for Lys-pNA.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politecnino Nacional (IPN), Centro Operativo Naranjo, Apartado Postal CON 174, Jaime Torres Bodet No. 142 Col Sta. Ma. la Ribera. CP 06401, Mexico, DF, Mexico.
authors.forename: Yuridia
authors.initials: Y
authors.lastname: Mercado-Flores
authors.forename: Yamilet
authors.initials: Y
authors.lastname: Noriega-Reyes
authors.forename: Bernardo
authors.initials: B
authors.lastname: Ramírez-Zavala
authors.forename: César
authors.initials: C
authors.lastname: Hernández-Rodríguez
authors.forename: Lourdes
authors.initials: L
authors.lastname: Villa-Tanaca
mesh_terms: D000626:Aminopeptidases / Q000302:isolation & purification* / Q000378:metabolism*; D002413:Cations, Divalent / Q000494:pharmacology; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013816:Thermodynamics; D014588:Ustilago / Q000201:enzymology*
chemical_list: D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D000626:Aminopeptidases