title: Purification and characterization of a lysine aminopeptidase from Kluyveromyces marxianus.
abstract: A lysine aminopeptidase was purified from the yeast Kluyveromyces marxianus. This enzyme was purified 100-fold from a soluble extract obtained at 100,000g. The purification procedure consisted in fractionated precipitation with ammonium sulfate and five chromatography steps. The native enzyme had a molecular mass of 46 kDa assessed through gel filtration. This aminopeptidase depicted an optimal pH of 7.0 and was stable at a pH range of 4-8, its optimal temperature was 45 degrees C and the enzyme became unstable at temperatures above 55 degrees C. The isoelectric point of the purified enzyme was 4.4. Michaelis constant and Vmax for L-lysine-p-nitroanilide were 0.33 mM and 2.2 mM min(-1) per milligram of protein, respectively. The enzyme was strongly inhibited by bestatin, o-phenanthroline and, to a lesser extent, by EDTA, suggesting that this enzyme is a metalloprotease. Our results suggest that the lysine aminopeptidase from Kluyveromyces marxianus might be of biotechnological relevance.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Apartado postal CON 174, C.P. 06400, México D.F., Mexico.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Ramírez-Zavala
authors.forename: Yuridia
authors.initials: Y
authors.lastname: Mercado-Flores
authors.forename: César
authors.initials: C
authors.lastname: Hernández-Rodríguez
authors.forename: Lourdes
authors.initials: L
authors.lastname: Villa-Tanaca
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D001709:Biotechnology / Q000379:methods; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007716:Kluyveromyces / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000626:Aminopeptidases; C056860:lysyl aminopeptidase