For decades the interaction of the anticholinesterase organophosphorus compounds with acetylcholinesterase has been characterized as a straightforward phosphylation of the active site serine (Ser-203) which can be described kinetically by the inhibitory rate constant k(i). However, more recently certain kinetic complexities in the inhibition of acetylcholinesterase by organophosphates such as p...

Phosphotriesterase was engineered into a spontaneously forming trimer by appending it to a synthetic collagen-like triple-helix motif. Enzymatic hydrolysis of the insecticide and organophosphate nerve agent simulant paraoxon was then examined. Assembling the phosphotriesterase trimer onto semiconductor quantum dots increased the enzyme's catalytic rate and efficiency.

Two robust catechol-functionalized porous organic polymers (catPOPs) with different Td-directing nodes were synthesized using a cobalt-catalyzed acetylene trimerization (CCAT) strategy. Postsynthesis metallation was readily carried out with La(acac)3 to afford catalytically active Lafunctionalized catPOPs for the solvolytic and hydrolytic degradation of the toxic organophosphate compound methyl...

Exposure to organophosphorus toxins induces seizures that progress to status epilepticus (SE), which can cause brain damage or death. Seizures are generated by hyperstimulation of muscarinic receptors, subsequent to inhibition of acetylcholinesterase; this is followed by glutamatergic hyperactivity, which sustains and reinforces seizure activity. It has been unclear which muscarinic receptor su...

Neurotoxic esterase activity was measured in homogenates of human placenta and hen brain, spinal cord, liver, kidney and spleen. The activity in liver comprised less than 20% of the Paraoxon-resistant esterases, but in the other tissues neurotoxic esterase accounted for over 50%. The same tissues were labelled with [3H]di-isopropyl phosphorofluoridate, and any isopropyl group transferred on to ...

Thrombin is a key serine protease involved in the blood cascade. Two small molecular inhibitors, 4-nitrophenyl diethylphosphate (paraoxon) and 4-nitrophenyl 2-propyl methylphosphonate (MPNP), covalently bond to the active-site Ser to form a mimic of the tetrahedral intermediate found in thrombin-catalyzed reactions. The pH dependence of their inhibition of human α-thrombin at 25.0 + 0.1C was de...

The ability of the enzyme organophosphorus acid anhydrolase (OPAA) to selectively hydrolyze the P–F bond of fluorine containing organophosphates has been used to develop a biosensor for specific detection of these compounds. Hydrolysis rate of diisopropyl fluorophosphate (DFP), paraoxon and demeton-S, by soluble and immobilized OPAA was measured. These compounds were selected as representative ...