[Interaction of bis-phosphorylated methanes with mammalian esterases].

The research article details the interaction of certain substances, specifically bis-phosphorylated methanes or compounds (insecticides), with various types of mammalian esterases. The study found that these compounds may irreversibly inhibit the function of the enzymes and show more selective behavior towards butyrylcholinesterase because of effective binding and hydrophobic interaction.

Interaction and Hydrolysis of Esterases

• The study investigated the interaction of certain insecticides known as bis-phosphorylated methanes with three types of mammalian esterases: human erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase, and rat liver carboxylesterase.
• It was found that the type I and II compounds of these insecticides were not hydrolyzed by carboxylesterase, indicating they were not broken down by this particular enzyme.
• Moreover, these compounds inhibited the esterases irreversibly, effectively stopping the regular functioning of these enzymes.

Inhibition through Enzyme-Inhibitor Complex Formation

• The research observed a complex pattern of inhibition of acetylcholinesterase and butyrylcholinesterase by these compounds.
• This inhibition was due to the formation of an enzyme-inhibitor complex, which was risked by the compounds’ presence.

Selective Behaviour of Compounds Towards Butyrylcholinesterase

• The compounds displayed more selectiveness towards butyrylcholinesterase compared to acetylcholinesterase and carboxylesterase, with their selectiveness or inhibition rate towards butyrylcholinesterase being by two orders of magnitude higher.
• This selectiveness is due to effective binding in the butyrylcholinesterase active center, facilitated through hydrophobic interaction, with K alpha ranging between 10(-8)–10(-9) M.

Role of Thion-Phosphoryl-Containing Fragment

• The study also established the important role of the thion-phosphoryl-containing fragment in the interaction of type II compounds with the active centers’ hydrophobic sites of butyrylcholinesterase and carboxylesterase.