Esterases from the greenbug associated with resistance to organophosphate insecticides were partially purified from both resistant and susceptible strains by ion-exchange chromatography and preparative electrophoresis. Enzymes from both strains exhibited similar elution profiles although the activity peak from the resistant strain was greater in both height and total area. The dominant esterase isozymes from both resistant and susceptible strains were further purified by preparative native electrophoresis. Kinetic analysis of the resulting enzyme indicated that the Km of the esterase was identical for the two strains, although Vmax was consistently three- five-fold higher in the resistant strain. Inhibition of the activity from both strains by paraoxon was also identical, providing further support for the presence of the same isozyme in the two strains. These results suggest that resistance is associated with overproduction of an isozyme present in the susceptible strain rather than the presence of an enzyme with altered properties.
|Original language||English (US)|
|Number of pages||6|
|Journal||Pesticide Biochemistry and Physiology|
|State||Published - Jun 1994|
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Health, Toxicology and Mutagenesis