tailieunhanh - Báo cáo khoa học: Rat butyrylcholinesterase-catalysed hydrolysis of N-alkyl homologues of benzoylcholine

The purpose of this work was to study the catalytic properties of rat buty-rylcholinesterase with benzoylcholine (BzCh) and N-alkyl derivatives of BzCh (BCHn) as substrates. Complex hysteretic behaviour was observed in the approach to steady-state kinetics for each ester. Hysteresis consisted of a long lag phase with damped oscillation. | ềFEBS Journal Rat butyrylcholinesterase-catalysed hydrolysis of N-alkyl homologues of benzoylcholine Anna Hrabovská1 2 Jean-Claude Debouzy3 Marie-Therese Froment2 Ferdinand Devinsky1 Ingrid Paulikova1 and Patrick Masson2 1 Comenius University Faculty of Pharmacy Department of Celland Molecular Biology of Drugs Bratislava Slovakia 2 Centre de Recherches du Service de Sante des Armees CRSSA Departement de Toxicologie Unites d Enzymologie La Tronche France 3 CRSSA Unite de Biophysique La Tronche France Keywords benzoylcholine butyrylcholinesterase cholinesterases damped oscillations hysteresis Correspondence A. Hrabovska Comenius University Faculty of Pharmacy Department of Cell and Molecular Biology of Drugs Kalinciakova 8 832 32 Bratislava Slovakia Fax 421 2 50 117100 Tel 421 2 50 117305 E-mail hrabovska@ Present address Laboratoire de la biologie des jonctions neuro-musculaires normales et pathologiques INSERM U686 45 rue des Saints-Peres 75006 Paris France Fax 33 1 42 86 33 99 Tel 33 1 42 86 40 95 E-mail Note The amino acid residue numbering is the same for both human and rat butyrylcholinesterase and is used throughout this work. Received 19 September 2005 revised 6 January 2006 accepted 17 January 2006 doi The purpose of this work was to study the catalytic properties of rat butyrylcholinesterase with benzoylcholine BzCh and N-alkyl derivatives of BzCh BCHn as substrates. Complex hysteretic behaviour was observed in the approach to steady-state kinetics for each ester. Hysteresis consisted of a long lag phase with damped oscillation. The presence of a long lag phase with no oscillations in substrate hydrolysis by rat butyrylcholinesterase was also observed with N-methylindoxyl acetate as substrate. Hysteretic behaviour was explained by the existence of two interconvertible butyrylcholinesterase forms in slow equilibrium while just one of them is catalytically active. The damped .