Inhibition kinetics of human serum butyrylcholinesterase by Cd2+, Zn2+ and Al3+: comparison of the effects of metal ions on cholinesterases |
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| Affiliation: | 1. Subatech CNRS/IN2P3-Université de Nantes-IMTA, 4 rue Alfred Kastler, F-44307 Nantes, France;2. CENBG, CNRS/IN2 P3, Chemin du Solarium, B.P. 120, F-33175 Gradignan, France;3. Prokerno Corp., Apartado Postal 0823-04789, Panamá - Bella Vista, Panama;4. IPHC CNRS/IN2P3, 23 rue du Loess, B.P. 28, F-67037 Strasbourg, France;1. Department of Chemistry, Vaal University of Technology, Vanderbijlpark 1900, South Africa;2. Nanoscience Research, Department of Industrial Chemistry, Federal University Oye Ekiti, P.M.B 373, Oye Ekiti, Ekiti State, Nigeria;1. INRA, UMR 1347 Agroécologie, 17 rue Sully, BP 86510, 21065 Dijon Cedex, France;2. Irstea, Centre de Lyon-Villeurbanne, UR MALY, 5 rue de la Doua, CS 70077, 69626 Villeurbanne Cedex, France;1. Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, PR China;2. Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou 310014, PR China;1. National School of Engineering Sfax, GEET, Tunisia;2. Department of Chemistry, Faculty of Sciences of Sfax, University of Sfax, Tunisia;1. Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka 585106, India;2. Department of Chemistry, Karnataka College, Bidar, Karnataka 585401, India |
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| Abstract: | Butyrylcholinesterase (BChE, EC 3.1.1.8) has been purified about 6600-fold from human serum with a procedure including ammonium sulfate fractionation (55–70%) with acid step at pH 4.5 and procainamide–Sepharose 4B affinity chromatography. The purified enzyme exhibited negative cooperativity with respect to butyrylthiocholine (BTCh) binding at pH 7.5. KS was found to be 0.128±0.012 mM. Inhibition kinetics of the enzyme by Cd2+, Zn2+ and Al3+ were studied in detail. The 1/v vs 1/[BTCh] plots in the absence (control plot) and in the presence of different concentrations of cations intersected above 1/[BTCh]-axis. The data were analyzed by means of a nonlinear curve fitting program. The results demonstrated that all of the three cations are the linear mixed-type inhibitors of BChE. Ca2+ and Mg2+ had no effect on the enzyme activity in the experimental conditions. But when the enzyme was inhibited by 0.5 mM Cd2+ or Zn2+, Ca2+ and Mg2+ partially reactivated the inhibited allosteric form of BChE. Results were compared with data obtained from brain BChE purified from sheep. |
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