title: The effects of Ni2+, Co2+, and Mn2+ on human serum butyrylcholinesterase.
abstract: The effects of Ni2+, Co2+, and Mn2+ on human serum butyrylcholinesterase (BChE, acylcholine acylhydrolase E.C. 3.1.1.8) were investigated in this study. Inhibition kinetics of BChE were studied using butyrylthiocholine (BTCh) as substrate. The "1/v" versus "1/[BTCh]" plots in the absence (control plot) and in the presence of the metal ions intersected above 1/[BTCh]-axis for all trace elements. In addition, when the concentrations of the cations were increased at 4 mM BTCh, velocities decreased and drove to zero at high concentrations of the trace elements. These results demonstrate that Ni2+, Co2+, and Mn2+ are linear mixed-type inhibitors of BChE. alphaK(i) values have been determined as 53.20 mM,152.25 mM, and 190.24 mM for Ni2+, Mn2+, and Co2+, respectively, by using nonlinear regression analysis. From the comparison of alphaK(i) values of the trace elements, it can be said that BChE has more affinty to binding Ni2+ than Co2+ and Mn2+.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Hacettepe University, 06100 Ankara, Turkey. ncokugras@superonline.com
authors.forename: A Neşe
authors.initials: AN
authors.lastname: Cokuğraş
authors.forename: Doğan
authors.initials: D
authors.lastname: Cengiz
authors.forename: E Ferhan
authors.initials: EF
authors.lastname: Tezcan
mesh_terms: D002091:Butyrylcholinesterase / Q000097:blood*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D003035:Cobalt / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology*; D009532:Nickel / Q000494:pharmacology*
chemical_list: D002800:Cholinesterase Inhibitors; D003035:Cobalt; D008345:Manganese; D009532:Nickel; D002091:Butyrylcholinesterase