Inhibition of Catalytic Activity of Horse Blood Serum Butyrylcholinesterase by High Concentrations of a Substrate, N-methyl-N-(β-acetoxyethyl)piperidinium

The kinetics of hydrolysis of N-methyl-N-(β-acetoxyethyl)-piperidinium by highly purified horse blood serum butyrylcholinesterase is studied at pH 7.5 and 25°C. A pronounced inhibition of catalytic activity of this enzyme by high concentrations of the substrate is revealed. The substrate inhibition can be explained either by interaction of the acylated enzyme with substrate with formation of the corresponding inactive complex ES'S or by sorption of substrate outside the enzyme active center and the resulted conformational changes of the enzyme molecule.[PUBLICATION ABSTRACT]