Phosphotriesterase (PTE)

Phosphotriesterase is an enzyme found in certain soil bacteria (notably Pseudomonas diminuta and Flavobacterium species) that catalyzes the hydrolysis of organophosphate triesters, which include a wide range of toxic pesticides and chemical warfare agents such as sarin and paraoxon. The enzyme features a (β/α)₈ TIM-barrel protein fold with a binuclear metal active site—typically zinc—that is essential for its catalytic activity. Notably, PTE has an extremely broad substrate specificity and can hydrolyze various synthetic organophosphates at rates approaching the diffusion limit, though it does not have a known natural physiological substrate. Due to its role in rapidly detoxifying neurotoxic organophosphates, PTE has been extensively studied as a candidate for bioremediation and as a bioscavenger to protect against poisoning and nerve agent exposure. Directed evolution and protein engineering have produced variants with enhanced activity and specificity for particular organophosphate substrates relevant to defense and public health applications.

Other names

AryldialkylphosphataseOrganophosphate hydrolaseOpdA (specific ortholog from Agrobacterium radiobacter)Organophosphate degrading enzyme

Catalyzes hydrolysis of phosphorus-oxygen or phosphorus-fluorine bonds in organophosphates, converting toxic compounds to non-toxic metabolites. Metal-ion-assisted nucleophilic substitution (often via two Zn²⁺ ions at the active site).