Cholinesterase: substrate inhibition and substrate activation.
The relationship between activities and substrate concentrations (pS-curves) was analysed for reactions of acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8). Catalytic constants Km, Kss, Vm, n and b were calculated from the Michaelis, Haldane, Hill and Webb equations in order to assess whether a given substrate also acts as an inhibitor or activator. It is suggested that the term substrate inhibition should only be attributed to substrates revealing bell-shaped pS-curves, while the terms apparent substrate inhibition or apparent substrate activation should relate to calculated values of the catalytic constants.
Reiner
E
E
Institute for Medical Research and Occupational Health, Zagreb, Croatia.
Simeon-Rudolf
V
V
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002091:Butyrylcholinesterase / Q000378:metabolism*; D002384:Catalysis; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008954:Models, Biological; D013379:Substrate Specificity
D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase