Cholinesterases

摘要: Cholinesterases (ChEs)—acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)—are of special concern to the toxicology pesticides. This chapter discusses ChEs, their importance in understanding toxicity organophosphate esters (OPs) carbamate pesticides (CBs), application risk assessment anticholinesterase other agents. ChEs are specialized carboxylic ester hydrolases that break down choline. The knowledge three-dimensional structure has led a better mechanisms action drugs chemical agents inhibit hydrolysis choline esters. In general, there three major domains for inhibitors bind: acyl pockets active center, peripheral anionic site. CBs OP enzyme activity by acting as alternate substrates acetylcholine (Ach). toxicities OPs often correlated with extent inhibitions brain AChE. One example carboxyesterase is serum paraoxonase (PON1), an A-esterase associated high-density plasma lipoproteins; PON1 destroys such oxon analogs parathion chlorpyrifos. Direct evidence its role detoxifying was provided showing mice exposed chlorpyrifos were protected against cholinesterase inhibition administration purified PON1.