title: Ligand-induced conformational changes in prolyl oligopeptidase: a kinetic approach.
abstract: Most kinetic studies of prolyl oligopeptidase (PREP) were performed with the porcine enzyme using modified peptide substrates. Yet recent biophysical studies used the human homolog. Therefore, the aim of this study was to compare the kinetic behavior of human and porcine PREP, as well as to find a suitable method to study enzyme kinetics with an unmodified biological substrate. It was found that human PREP behaves identically to the porcine homolog, displaying a double bell-shaped pH profile and a pH-dependent solvent kinetic isotope effect of the kcat/Km, features that set it apart from the related exopeptidase dipeptidyl peptidase IV (DPP IV). However, the empirical temperature coefficient Q10, describing the temperature dependency of the kinetic parameters and the non-linear Arrhenius plot of kcat/Km are common characteristics between PREP and DPP IV. The results also demonstrate the feasibility of microcalorimetry for measuring turn-over of proline containing peptides.
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Van Elzen
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Schoenmakers
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: I
authors.initials: I
authors.lastname: Brandt
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Van Der Veken
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: A M
authors.initials: AM
authors.lastname: Lambeir
mesh_terms: D000818:Animals; D004795:Enzyme Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism; D000072417:Protein Domains; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D013552:Swine
chemical_list: D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; C514899:PREP protein, human; D012697:Serine Endopeptidases
keywords: bradykinin; isothermal titration calorimetry; proline; serine protease