Non-specific esterases in mites-a comparative study

1. A variety of non-specific cytosolic and solubilized microsomal esterase isozymes from three mite species Rhizoglyphus robini, Tetranychus urticae and Phytoseiulus persimilis, representing three different acarine suborders, were separated by polyacrylamide electrophoresis. 2. The relevance of enzyme heterogeneity with respect to habitats and tolerance to pesticides of these mites is discussed. 3. The kinetics of the separated esterase isozymes, which were measured directly on the acrylamide gel, revealed a diversity of intra- and interspecific K_m values. 4. Most of the esterase isozymes present in the cytosolic and microsomal fractions were sensitive to the organophosphorus compound diisopropyi fluorophosphate. 5. They were less inhibited by the carbamate eserine and by p-hydroxymercuribenzoate. 6. The enzymes were highly sensitive to transition state analogs represented by several trifluoroketones.