title: Genetic and biochemical studies of the highly active esterases A' and B associated with organophosphate resistance in mosquitoes of the Culex pipiens complex.
abstract: The highly active esterases A' and B that cannot be dissociated from OP resistance in Culex pipiens from France and California are shown to have equivalent Km values (2.1 x 10(-6) M/min/mosquito) but different turnover rates (Vm = 2.13 and 0.57  x 10(-6) M/min/mosquito, respectively) and pH for maximum activity. Both enzymes have broad substrate specificities and at least one, esterase A', can hydrolyze OP insecticides. In addition, esterases A' and B are coded by two closely linked genes, Est-3 and Est-2, respectively (0.67 unit of crossing over), located on the same autosome as pl, a locus attributed to linkage group III. The estimated distance between Est-2 and pl was 9.4 units.
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D009033:Culicidae / Q000235:genetics*; D004950:Esterases / Q000235:genetics*; D005260:Female; D005796:Genes; D008040:Genetic Linkage; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology; D008297:Male; D009943:Organophosphorus Compounds
chemical_list: D007306:Insecticides; D009943:Organophosphorus Compounds; D004950:Esterases