Organophosphorus hydrolase

Cho T-H, Wild JR, Connelly KC. 2000. Utility of organophosphorus hydrolase for the remediation of mutagenicity of methyl parathion. Environ Toxicol Chem 19(8) 2022-2028. 

Comparison of whole cell biocatalytic reaction kinetics for recombinant Escherichia coli with periplasmic-secreting or cytoplasmic-expressing organophosphorus hydrolase... 

Shimazu, M., Mulchandani, A. and Chen, W. (2001) Cell surface display of organophosphorus hydrolase using ice nucleation protein. Biotechnology Progress, 17, 76-80. 

A. Mulchandani, P. Mulchnadani, W. Chen, J. Wang, and L. Chen, Amperometric thick-film strip electrodes for monitoring organophosphate nerve agents based on immobilized organophosphorus hydrolase. Anal. Chem. 71, 2246-2249 (1999). 

A. Mulchandani, I. Kaneva, and W. Chen, Biosensor for direct determination of organophosphate nerve agents using recombinant Escherichia coli with surface-expressed organophosphorus hydrolase. 2. Fiber-optic microbial biosensor. Anal. Chem. 70, 5042-5046 (1998). 

R.P. Deo, J. Wang, I. Block, A. Mulchandani, K.A. Joshi, M. Trojaowicz, F. Scholz, W. Chen, and Y. Lin, Determination of organophosphate pesticides at a carbon nanotube/organophosphorus hydrolase electrochemical biosensor. Anal. Chim. Acta 530, 185—189 (2005). 

LeJeune KE, Swers IS et al (1999) Increasing the tolerance of organophosphorus hydrolase to bleach. Biotechnol Bioeng 64(2) 250-254... 

Environmental application for bioremediation purposes must also get the benefit of the technology. Since haloalkane dehalogenase activity was tested successfully, as shown in Example 2 above for the dehalogenation of toxic VOCs, many others enzymatic activities should be of great interest, such as oxygenases, nitrilases, and organophosphorus hydrolases, for example. 

LeJeune et al. - - investigated this stabilizing effect of immobilization at the expense of activity. They immobilized an organophosphorus hydrolase by emulsifying a solution of the enzyme with a hydrophilic polyurethane prepolymer. They intended to study the enzymatically catalyzed hydrolysis of organophosphate nerve... 

Another important problem is the development of insects resistant to insecticides. This often arises as a result of increased levels of carboxylesterases which hydrolyze both organophosphates and car-baryl.h/1 A mutation that changed a single active site glycine to aspartate in a carboxylesterase of a blowfly changed the esterase to an organophosphorus hydrolase which protected the fly against insecticides.)... 

Figure 1 Proposed mechanism for paraoxon hydrolysis by organophosphorus hydrolase (X and X are unspecified ligands).

Newcomb, R.D., Campbell, P.M., Ollis, D.L., Cheah, E., Russell, R.J., and Oakeshott, J.G., A single amino acid substitution converts a carboxylesterase to an organophosphorus hydrolase and confers insecticide resistance on a blow fly, Proc. Natl. Acad. Sci. USA, 94, 7464,1997. 

Gopal, S., Rastogi, V., Ashman, W., Mulbry, W. (2000). Mutagenesis of organophosphorus hydrolase to enhance hydrolysis of the nerve agent VX. Biochem. Biophys. Res. Commun. 279 516-19. 

Grimsley, J.K., Calamini, B., Wild, J.R., Mesecar, A.D. (2005). Structural and mutational studies of organophosphorus hydrolase reveal a cryptic and functional allosteric-binding site. Arch. Biochem. Biophys. 442 169-79. 

In contrast to the inhibition mode of detection in the above biosensors, a direct detection of OP compounds has been proposed by means of organophosphorus hydrolase (OPH) enzymes, which hydrolyze OP compounds as shown in Scheme 55.6. OPH enzymes have a rather wide spectrum of substrate selectivity and hydrolyze many kinds of OP compounds including OP pesticides, VX, and sarin. It is... 

Walker, J.P., Kimble, K.W., Asher, S.A. (2007). Photonic crystal sensor for organophosphate nerve agents utilizing the organophosphorus hydrolase enzyme. Anal. Bioanal. Chem. 389 2115-24. 

Fig. 10.10. Reaction scheme of the organophosphorus hydrolase cateJysed reaction of parathion and the electrochemical detection of the product p-nitrophenol.

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