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List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Demeton-S-methyl is highly toxic to animals and humans. Careless occupational exposures to demeton-S-methyl cause severe symptoms of poisoning that include, but are not limited to, headaches, nausea, vomiting, diarrhea, sweating, dizziness, tremors, lack of coordination, hiccough, and memory loss. Prolonged exposures to high concentrations cause pupillary constriction, blurred vision, muscle cramp, excessive salivation, weakness, sweating, abdominal cramps, unconsciousness, respiratory distress, convulsions, respiratory failure, and death.
A comprehensive review on enzymatic degradation of the organophosphate pesticide malathion in the environment
Published in Journal of Environmental Science and Health, Part C, 2019
Smita S. Kumar, Pooja Ghosh, Sandeep K. Malyan, Jyoti Sharma, Vivek Kumar
Organophosphorus hydrolase (OPH) obtained from bacteria is encoded by the opd gene (organophosphate degrading). It has been purified from Pseudomonas diminuta and Flavobacterium sp strain ATCC27551 and attacks various phosphoester bonds including P-O, P-CN, P-F, and P-S. However, the efficiency of cleavage of different bonds is different. For example, the rate of catalysis of the P-S bond is approximately 1000 times slower as compared to that of the P-O bond. So as to improve the specificity and efficiency of OPH, other variants have been created by intended and arbitrary approaches. Both of these approaches rely on mutagenesis of the opd gene followed by screening against the target of choice to optimize the mutant enzyme for a specific target. Very few studies have attempted to generate improved enzymes for P-S organophosphates. Schofield et al.108 carried out a study in order to generate an OPH variant with improved hydrolytic efficiency against the remediation of P-S organophosphates. Site-directed mutagenesis and saturation mutagenesis of active site residues followed by screening against demeton-S methyl and malathion were sequentially performed to identify variants with improved hydrolytic efficiency.