Characterization of the transient oxaphosphetane BChE inhibitor formed from spontaneously activated ethephon

Abstract

The major plant growth regulator ethephon degrades to ethylene and phosphate in aqueous solutions and plants and is spontaneously activated to a butyrylcholinesterase (BChE) inhibitor in alkaline solutions and animal tissues. In the present 31P NMR kinetic study of the reactions of ethephon in pH 7.4 carbonate buffer, we observed a transient peak at 28.11 ppm. The time course for the appearance and disappearance of this peak matches the activation/degradation kinetic profile of the BChE inhibitor, and the chemical shift supports the proposed 2-oxo-2-hydroxy-1,2-oxaphosphetane structure. © 2013 American Chemical Society.