Spontaneous reactivation of phosphinylated human erythrocyte acetylcholinesterase and human serum butyrylcholinesterase.

This report documents studies on the spontaneous reactivation of human erythrocyte acetylcholinesterase and human serum butyrylcholinesterase following inhibition by organophosphinate esters. The spontaneous reactivation reactions were carried out at 26.0 degrees C in 0.10 M phosphate buffer of pH 7.6. Based upon results at 24 h, human serum butyrylcholinesterase inhibited with 4-nitrophenyl methyl (4-methoxyphenyl) phosphinate was the most responsive (92.5% recovery) of the nine esters studied. Using the same criteria, the most active compound in the human erythrocyte acetylcholinesterase studies was 4-nitrophenyl methyl(phenyl)phosphinate (74.2% recovery). With seven of the nine compounds examined the response was greater from the serum enzyme than from the erythrocyte enzyme.