The preparation and kinetic analysis of multiple forms of human erythrocyte acetylcholinesterase.
A method for preparing various forms of acetylcholinesterase (AChE) from human erythrocyte has been established and they have been characterized in terms of kinetic parameters such as K(m), rate constant (k), turnover number (kcat), specificity constant (ksp), Vmax, half-life (t1/2), IC50 and Ki for tetrabutylammonium hydroxide, procaine and physostigmine in the present study. The solubility experiments show that, there is one major form of AChE i.e. membrane bound AChE (MBAChE) and one minor form i.e. water soluble form (WSAChE). The MBAChE shows several subforms, and on the basis of percentage activity only three MBAChE forms have been selected for complete characterization by various kinetic parameters and found that these three forms of MBAChE demonstrate significant differences in their kinetic properties except IC50. This study supports the recommendation of the use of these kinetic parameters as a tool for the analysis of the multiple forms of the various enzymes in the biological systems.
Kamal
M A
MA
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
al-Jafari
A A
AA
D000110:Acetylcholinesterase / Q000097:blood* / Q000302:isolation & purification; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D003902:Detergents; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000097:blood* / Q000302:isolation & purification; D007700:Kinetics; D008297:Male; D017830:Octoxynol; D010830:Physostigmine; D011343:Procaine; D000644:Quaternary Ammonium Compounds; D012016:Reference Values; D012965:Sodium Chloride
D002800:Cholinesterase Inhibitors; D003902:Detergents; D007527:Isoenzymes; D000644:Quaternary Ammonium Compounds; D012965:Sodium Chloride; D011343:Procaine; D017830:Octoxynol; D010830:Physostigmine; C009405:tetrabutylammonium; D000110:Acetylcholinesterase