DFPase can hydrolyze the P-F bond of diisopropyl phosphate fluoride (DFP) to produce diisopropyl phosphate and HF. In this article, the activity of two kinds of DFPase from porcine liver was assayed by the methods of titration and F- ion sensitive electrode. The results showed that the activity of large molecular DFPase can be determined by both methods, but the activity of small molecular DFPa...

In a preceding paper (1)) evidence has been presented that two enzymes of hog kidney, dialkylfluorophosphatase (2) and amino acid Acylase I (3) are separate and distinct enzymes (4). The DFPasesl are widely distributed (5, 6) ; naturally occurring substrates are unknown although these enzymes bear some resemblances to peptidases and esterases. It was also noted that there was some correlation b...

Di-isopropylfluorophosphatase (DFPase) is shown to contain two high-affinity Ca(2+)-binding sites, which are required for catalytic activity and stability. Incubation with chelating agents results in the irreversible inactivation of DFPase. From titrations with Quin 2 [2-([2-[bis(carboxymethyl)amino]-5-methylphenoxy]-methyl)-6-methoxy-8-[bis(carboxymethyl)-amino]quinoline], a lower-affinity sit...

Organophosphate hydrolases are proficient catalysts of the breakdown of neurotoxic organophosphates and have great potential as both biotherapeutics for treating acute organophosphate toxicity and as bioremediation agents. However, proficient organophosphatases such as serum paraoxonase 1 (PON1) and the organophosphate-hydrolyzing lactonase SsoPox are unable to hydrolyze bulkyorganophosphates w...

Hydrogen atoms constitute about half of all atoms in proteins and play a critical role in enzyme mechanisms and macromolecular and solvent structure. Hydrogen atom positions can readily be determined by neutron diffraction, and as such, neutron diffraction is an invaluable tool for elucidating molecular mechanisms. Joint refinement of neutron and X-ray diffraction data can lead to improved mode...

Organophosphorus (OP) nerve agents such as (S)-sarin are among the most highly toxic compounds that have been synthesized. Engineering enzymes that catalyze the hydrolysis of nerve agents ("bioscavengers") is an emerging prophylactic approach to diminish their toxic effects. Although its native function is not known, diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris catalyzes the hydr...

An enzyme purified from squid nerve that hydrolyzes the cholinesterase inhibitor diisopropyl phosphorofluoridate (DFP) has now been coupled to agarose beads. A column of this agarose-DFPase hydrolyzes the nerve gas 1,2,2-trimethylpropyl methylphosphonofluoridate (Soman). Although the more inhibitory of the four diastereoisomers of Soman are hydrolyzed least rapidly, a column of sufficient lengt...

The coaxial electrospinning technique was investigated as a novel method to create stabilized, enzyme-containing fibers that have the potential to provide enhanced protection from chemical agents. Electrospinning is a versatile technique for the fabrication of polymer fibers with large length (cm to km): diameter (nm to μm) aspect ratios. The large surface to volume ratios, along with the biofr...