What is the type of inhibition of acetylcholinesterase caused by organophosphates?
Ans. d. Competitive and irreversible (Ref: Goodman Gillman 12/e p242. Katzung 12/e p106: KDT 7/e p99)The type of inhibition of acetyl cholinesterase caused by organophosphates is competitive & irreversible."Organophosphates cause irreversible inhibition of Acetyl-cholinesterase while that caused by carbamates is reversible. Both bind at the esteratic site of the enzyme causing competitive inhibition."" Thus, the terms reversible and irreversible as applied to the carbamoyl ester and organophosphate anti-ChE agents, respectively: reflect only quantitative differences in rates of decarbamoylation or dephosphorylation of the conjugated enzyme. Both chemical classes react covalently with the active center serine in essentially the same manner as does ACh. "--Goodman Gillman 12/e p242AnticholinesterasesReversibleIrreversibleCarbamatesAcridineOrganophosphateCarbamates* Physostigmine* Neostigmine* Pyridostigmine* Edrophonium* Rivastigmine* Donepezil* Galantamine* Tacrine* Dyflos (DFP)* Echothiophate* Parathion* Malathion* Diazinon (TIK -20)* Tabun* Sarin* Soman* Carbaryl* Propoxur
Competitive and reversible
Noncompetitive and irreversible
Uncompetitive and reversible
Competitive and irreversible
Cholinergic System