Kinetics of human erythrocyte acetylcholinesterase inhibition by cis-diamminediaquaplatinum (II).
This work addresses the kinetic studies for the interaction of cis-diamminediaquaplatinum (II) ¿cis-[Pt(NH3)2(H2O)2]2+¿, (DDP) with human erythrocyte acetylcholinesterase (AChE). The Ks for the hydrolysis of acetylthiocholine iodide (ASCh) by AChE was 0.077 mM in the control system, the value decreased by 14-38% in the DDP treated systems. The Vmax was 1.34 mumole/min/mg protein for the control system while it was decreased by 26-57% in the DDP treated systems. The Lineweaver-Burk 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 and Ki were estimated as 0.203 and 0.096 mM, respectively. The estimated values of Ki and KI in the present investigation were compared with reported values for human erythrocyte and camel retina AChE inhibition by some antineoplastic drugs: cisplatin, cyclophosphamide and methotrexate.
Kamal
M A
MA
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
D000110:Acetylcholinesterase / Q000097:blood* / Q000378:metabolism; D000818:Animals; D002162:Camelus; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D002945:Cisplatin / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D008727:Methotrexate / Q000494:pharmacology; D008956:Models, Chemical; D012160:Retina / Q000201:enzymology
D002800:Cholinesterase Inhibitors; D000110:Acetylcholinesterase; D002945:Cisplatin; D008727:Methotrexate