caa a22 4500 477118984 CHVBK 20180405111630.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF00226062 doi (NATIONALLICENCE)springer-10.1007/BF00226062 In vitro inhibition of human erythrocyte acetylcholinesterase (EC3.1.1.7) by an antineoplastic drug methotrexate [Elektronische Daten] [Mohammad Kamal, Faizul Nasim, Abdulaziz Al-Jafari] This work addresses the kinetic analysis of the interaction of methotrexate (MTX) with human erythrocyte membrane-bound acetylcholinesterase (AChE, EC 3.1. 1.7). It was found that the MTX effect was independent of time of incubation with AChE before the addition of substrate which proves its reversible action. The IC50 was determined, by three methods, to be 0.73 mM. The Michaelis-Menten constant (Ks) for the hydrolysis of acetylthiocholine iodide (ASCh) by AChE was 0.13 mM in the control system, a value decreased by 30-61% in the MTX treated systems. The Vmax was 1.27μtmole/min/mg protein for the control system while it was decreased by 44-77% in the MTX treated systems. The Linexveaver-Buck plot, Dixon plot, and their secondary replots indicated that the nature of the inhibition was of the linear mixed type, i.e. uncompetitive and noncompetitive. The values of Ki(slope) and KI(tntecept) were estimated as 1.67 and 0.34 mM, respectively. Kluwer Academic Publishers, 1996 acetylcholinesterase nationallicence kinetics nationallicence inhibition nationallicence methotrexate nationallicence anticancer drugs nationallicence human erythrocyte nationallicence AChE : acetylcholinesterase nationallicence ASCh : acetylthiocholine nationallicence Ks : Michaelis-Menten constant nationallicence Vmax : the limiting maximal velocity nationallicence Ki : inhibition constant nationallicence MTX : methotrexate nationallicence Kamal Mohammad Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia aut Nasim Faizul Department of Pharmacy, Islamia University, Bahawalpur, Pakistan aut Al-Jafari Abdulaziz Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 159/1(1996-06-01), 47-53 0300-8177 159:1<47 1996 159 11010 https://doi.org/10.1007/BF00226062 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00226062 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kamal Mohammad Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia aut NATIONALLICENCE 700 1- Nasim Faizul Department of Pharmacy, Islamia University, Bahawalpur, Pakistan aut NATIONALLICENCE 700 1- Al-Jafari Abdulaziz Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 159/1(1996-06-01), 47-53 0300-8177 159:1<47 1996 159 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer