Type: Research Essays
Sample donated: Holly Rowe
Last updated: August 13, 2019
The application of pesticides has facilitated thedevelopment and expansion of agriculture globally. Organophosphates belong to aclass of highly toxic neurotoxins that are commonly used as insecticides andchemical warfare agents (Surekha Rani et al. 2008).The continuous use of organophosphates in intensive quantities throughout theworld and their potential neurotoxicity to humans has led to the development ofvarious efficient and safe bioremediation strategies to deal with their widedispersal in the ecosystem (Cho et al. 2002). Enzymatic degradation byorganophosphorus hydrolase (OPH) has received considerable attention since itprovides the possibility of both eco friendly and in situ detoxification(Catherine et al.
2002). The focus of this work is organophosphorushydrolase (OPH, E.C. 184.108.40.206), which catalyzes the hydrolysis of manyorganophosphorus compounds and greatly reduces the toxicity and even cancompletely mineralize them.Identical opd genes coding for OPH were foundin two soil microorganisms, Pseudomonas diminuta MG and Flavobacteriumsp.
(Sethunathan et al. 1998). AlthoughOPH hydrolyzes a wide range of organophosphates, the effectiveness ofhydrolysis varies dramatically. Widely used organophosphorus insecticides likemethyl parathion, chlorpyrifos, and diazinon are hydrolyzed 30 to 1,000 timesslower than is the preferred substrate, paraoxon (Cho et al. 2002). Thisreduction in catalytic rate is due to the unfavorable interaction of thesesubstrates with the active sites involved in catalysis and/or structuralfunctions (Zheng et al. 2013). A number of enzymes are capable of hydrolysing abroad range of OP triesters into less or non-toxic compounds.
These enzymes arepossible bioremediators because of their ability to decontaminate OP-containingwaters and soils. The most thoroughly characterized phosphotriesterases havebeen isolated from Flavobacterium sp. ATCC 27551, Pseudomonasdiminuta (OPH) and Agrobacterium radiobacter (OpdA) (Fernanda et al.2010).
These enzymes belong to the binuclearmetallohydrolase family and share high sequence and structural homology.Phosphotriesterases are highly promiscuous enzymes, hydrolysing a large rangeof substrates. The mechanism of phosphotriester hydrolysis by OPH has beenstudied extensively (Castro et al. 2016). Ina proposed reaction scheme based largely on crystal structures with boundinhibitors, the phosphoryl oxygen of the substrate binds to the ?-metalion (Janet et al.2005).
In the present research focuses on the interactionand degradation of chlorpyrifos by OPH enzyme, as this is responsible fordetoxification. The molecular docking study was conducted under FlexX dockingsoftware package.