A dehydrochlorinase-based pH change assay for determination of DDT in sprayed surfaces

Analytical Biochemistry
Evangelia MorouJohn Vontas

Abstract

A glutathione S-transferase (GST) from the mosquito Aedes aegypti (aagste2), selected in the field as a major metabolic resistance enzyme for this parasite vector, was employed to produce a highly specific assay for the determination of DDT [1,1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]. Detection is based on the pH change occurring in an appropriate buffer system by the concomitant release of H(+) during the aagste2-catalyzed dehydrochlorination reaction and is monitored potentiometrically or colorimetrically in the presence of a pH marker. The theoretical limit of detection (LOD) of the assay is 3.8 microg/ml, and the linear range of quantification is 12 to 250 microg/ml. The method does not recognize biologically inactive DDT analogues or major DDT photodegradants and breakdown molecules, and it is highly specific for the insecticidal p.p'DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. The biosensor was validated with a number of insecticide swabs from DDT-sprayed surfaces and found to be reproducible and reliable as compared with high-performance liquid chromatography (HPLC) (correlation coefficient R(2)=0.98). Given the current expansion of DDT residual sprayings in many regions of Africa as a key strategic interve...Continue Reading

References

Oct 1, 1974·Proceedings of the National Academy of Sciences of the United States of America·W H HabigW B Jakoby
Nov 24, 2004·Protein Engineering, Design & Selection : PEDS·Nikolaos E LabrouYannis D Clonis
Mar 23, 2005·Transactions of the Royal Society of Tropical Medicine and Hygiene·Ahmad Ali EnayatiJanet Hemingway
Jun 10, 2005·Insect Biochemistry and Molecular Biology·Nongkran LumjuanHilary Ranson
Jan 31, 2006·Biomolecular Engineering·Silvana Andreescu, Jean-Louis Marty

❮ Previous
Next ❯

Related Concepts

Related Feeds

Antimalarial Agents (ASM)

Antimalarial agents, also known as antimalarials, are designed to prevent or cure malaria. Discover the latest research on antimalarial agents here.

Antimalarial Agents

Antimalarial agents, also known as antimalarials, are designed to prevent or cure malaria. Discover the latest research on antimalarial agents here.