Purification and characterization of a carboxylesterase involved in malathion-specific resistance from Tribolium castaneum (Coleoptera: Tenebrionidae)

Abstract

Specific resistance to malathion in a strain of Tribolium castaneum is due to a 44-fold increase in malathion carboxylesterase (MCE) activity relative to a susceptible strain, whereas non-specific esterase levels are slightly lower. Unlike the overproduced esterase of some mosquito and aphid species, MCE in Tribolium castaneum accounts for only a small fraction (0.033-0.045%) of the total extractable protein respectively in resistant and susceptible strains. The enzyme was purified to apparent homogeneity from these two strains and has a similar molecular weight of 62,000. However, preparative isoelectricfocusing indicated that resistant insects possess one MCE with pI of 7.3, while susceptible insects possess a MCE with a pI of 6.6. Purified MCE from both populations had different K m and V m values for hydrolysis of malathion as well as for α-naphthyl acetate. The kinetic analysis suggests that MCE of resistant insects hydrolyses malathion faster than the purified carboxylesterase from susceptible beetles and that this enzyme has greater affinity for malathion than for naphthyl esters. Malathion-specific resistance is due to the presence of a qualitatively different esterase in the resistant strain.

Carboxylesterases from the seeds of an underutilized legume, Mucuna pruriens; isolation, purification and characterization

“…The low isoelectric pH values, the presence of large proportions of acidic amino acids and binding affinity to the anion exchanger clearly indicate the acidic nature of carboxylesterases in many cases. Eric Haubruge (2002) reported carboxylesterases of isoelectric pH values of 7.3 and 6.6 from malathion resistant and susceptible insects, Tribolium castaneum.…”

Expression and Characterization of Carboxylesterase E4 Gene from Peach–Potato Aphid (Myzus persicae) for Degradation of Carbaryl and Malathion

“…Malathion is probably detoxified through the hydrolysis of one or both of its two ethyl carboxylester groups (see Figure 1) particularly in view of non-esterified organophosphorus pesticides Dichlorovos and Parathion, not being attached by recombinant CbE E4. The carboxylesterase that hydrolyzes Malathion is widely distributed in mammals but only sporadically in insects, where in some cases it is responsible for insecticide resistance (Haubruge et al 2002).…”

Specificity of the fluorescein transport process in Malpighian tubules of the cricketAcheta domesticus

“…Haubruge et al, 2002;Hemingway et al, 2004;Pasteur et al, 2001). To date, a smaller number of studies have investigated the possibility that excretion of toxins may be an important survival mechanism in insects (e.g.…”

“…Haubruge et al, 2002;Pasteur et al, 2001). During acquisition of malathion resistance, carboxyesterases are commonly upregulated, increasing MMA production and diverting malathion away from the more toxic malathion oxon derivative (Fig.·7), which is not an organic anion transport substrate (Table·2).…”