Comparison of Cholinesterases and Carboxylesterase as Bioscavengers for Organophosphorus Compounds

Abstract

Inasmuch as the traditional pharmacological approaches to protection against organophosphorus (OP) compounds may be near their practical limits, a new approach using enzymes as bioscavengers has recently been examined. The feasibility of using bioscavengers, such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxylesterase (CaE), to provide protection against OP compounds has been demonstrated in rodents as well as nonhuman primates (1–5). The major advantages of bioscavengers for protection against OP toxicity are their rapid removal of OP compounds from circulation, their selective reactivities with the toxic stereoisomers of chiral compounds, and their relatively slow clearance from circulation. In comparison to other pharmacological approaches, the appeal of bioscavenger protection is that bioscavenger-protected survivors of exposure to OP compounds do not exhibit the postexposure incapacitation and toxic effects that are commonly observed with survivors protected by traditional antidotal approaches, such as oximes, anticholinergics, or carbamates (6).