Fensulfothion (CAS 115-90-2)

Fensulfothion is a yellow or brown, oily liquid used as an insecticide, nematocide, and mosquito larvicide, as reported by the EPA in 1998. It falls under the category of organic thiophosphates and sulfoxides and functions as an insecticide inhibiting the EC 3.1.1.7 enzyme (acetylcholinesterase). Additionally, it serves as an agrochemical, avicide, and nematicide, derived from a 4-(methylsulfinyl)phenol. Organophosphorus pesticides, like fensulfothion, exert their toxic effect primarily by inhibiting esterase enzyme activity, especially cholinesterase. These pesticides can also indirectly interact with acetylcholine′s biochemical receptors. When it comes to the reactivation of phosphorylated enzymes, such as acetylated acetylcholinesterase, these esters can be hydrolyzed by nucleophilic agents, including water. However, the rate of reactivation by water for phosphorylated enzymes is extremely low compared to acetylcholinesterase combined with acetate. Inhibition by isopropyl phosphate essentially results in a rate of reactivation close to zero. These findings contribute to the understanding of the mechanisms involved in the toxicity of organic phosphorus pesticides like fensulfothion.