Characterization of the transient oxaphosphetane BChE inhibitor formed from spontaneously activated ethephon.
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 (31)P 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.
Department of Nutritional Sciences and Toxicology, University of California, Berkeley , California 94720-3112, United States.
Stephen R
SR
Lantz
John E
JE
Casida
D002091:Butyrylcholinesterase / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010753:Phosphoranes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D002800:Cholinesterase Inhibitors; D009943:Organophosphorus Compounds; D010753:Phosphoranes; D002091:Butyrylcholinesterase; C005073:ethephon