Mechanism of stereoselective interaction between butyrylcholinesterase and ethopropazine enantiomers

► BChE reacts with ethopropazine enantiomers stereoselectively (specific inhibitor of BChE). ► Complex mechanism of BChE interaction with the ethopropazine was described. ► Inhibition of BChE by racemate can be described using kinetic constants derived for enantiomers. ► Three kinetic models for cholinesterases were compared in explaining inhibition mechanism. ► Various BChE showed similarity in stereoselectivity while AChE showed a lack of stereoselectivity.