properties of matter : Freeze-dried powder. from Horse Serum ≥4 U/ mg It catalyzes the hydrolysis of a number of choline esters according to the following reaction:Acylcholine + H2O → choline + acid It is a tetrameric glycoprotein with four subunits of equal size, each having a molecular weight of 110 kDa. Butyryl cholinesterase hydrolyzes butyrylcholine four times more rapidly than acetylcholine. It is inhibited by 10-5 M physostigmine, numerous organophosphate esters, the carbamate derivates and quaternary ammonium saltsunit hydrolyzes 1μmole of acetylchoine per minute at 25°C, pH 7.4.