title: Kinetic and computational analysis of the reversible inhibition of porcine pancreatic elastase: a structural and mechanistic approach.
abstract: Structural and mechanistic insights were revealed for the reversible inhibition of Porcine Pancreatic Elastase (PPE); the kinetics of uninhibited and inhibited hydrolysis of substrate Suc-AAA-pNA was analyzed thoroughly. Additionally, the interactions between PPE and its inhibitor were studied by computational techniques. The uninhibited hydrolysis of Suc-AAA-pNA by PPE proceeds through a virtual transition state, involving an inferior physical and another dominating chemical step, where two stabilized reactant states precede the predominant acyl-enzyme. Different kinds of bonding with the PPE-backbone residues, including those of the catalytic triad, were found during the MD simulation of 5 ns, as key interactions favoring a higher stabilization of the best ranked complex PPE-CF3C(O)-KA-NHPh-p-CF3. The proton inventories of the inhibited hydrolysis of Suc-AAA-pNA by PPE, were ruled out the existence of any virtual transition state and thus they argue for a different mode of catalysis involving a structurally disturbed PPE molecule. Thereafter, a novel inhibition mechanism was suggested.
authors.affiliation: a Department of Chemistry , Enzyme Biotechnology and Genetic Engineering Group, University of Ioannina , Ioannina , Greece and.
authors.forename: Panagiota-Yiolanda
authors.initials: PY
authors.lastname: Stergiou
authors.affiliation: a Department of Chemistry , Enzyme Biotechnology and Genetic Engineering Group, University of Ioannina , Ioannina , Greece and.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Foukis
authors.affiliation: a Department of Chemistry , Enzyme Biotechnology and Genetic Engineering Group, University of Ioannina , Ioannina , Greece and.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Gkini
authors.affiliation: b Laboratory of Enzymology-Unistra , University of Strasbourg , Strasbourg , France.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Bieth
authors.affiliation: a Department of Chemistry , Enzyme Biotechnology and Genetic Engineering Group, University of Ioannina , Ioannina , Greece and.
authors.forename: Emmanuel M
authors.initials: EM
authors.lastname: Papamichael
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D004791:Enzyme Inhibitors; D010196:Pancreatic Elastase
keywords: Inhibition mechanism; molecular docking; molecular dynamics; proton inventories