Resistance monooxygenases

Insect strains resistant Cypermethrin Monooxygenase Piperonyl butoxide (PBO) <200... 

Resistance mechanisms associated with changes in toxicokinetics are predominately cases of enhanced metabolic detoxication. With readily biodegradable insecticides such as pyrethroids and carbamates, enhanced detoxication by P450-based monooxygenase is a common resistance mechanism (see Table 4.3). 

A nnmber of other examples are known in which genetically based resistance was dne to enhanced detoxication of OPs. These include malathion resistance in some stored product pests owing to high carboxylesterase activity, and resistance of strains of the housefly to diazinon due to detoxication by specific forms of a glutathione-S-transferase and monooxygenase (Brooks 1972). 

Webb, R.E., Randolph, W.C., and Horsfall, E. Jr. (1972). Hepatic benzo(a)pyrene monooxygenase activity in endrin susceptible and resistant pine mice. Life Science 11 Part 2, 477 84. 

Despite comparatively low amounts of catalytic cycles, the currently designed monooxygenase catalytic system is highly effective and adaptable to manufacture, which is typical of flow systems. It is also extremely resistant to the effects of oxidants and high temperature [82],... 

The catalyst indicated extremely high resistance to the effects of oxidants and their intermediates and relatively high temperature, e.g. it preserves the ability to epoxidize during the whole time of the biomimic tests. Owing to the mentioned properties of the mimic, kinetic regularities of current monooxygenase reaction were studied in a broad range of reaction parameters with reproducible results. 

Mishina, T.E., Zeier, J. The Arabidopsis flavin-dependent monooxygenase FMOl is an essential component of biologically induced systemic acquired resistance. Plant Physiol 141 (2006) 1666-1675. 

Among the phase I reactions, oxidation mediated by cytochrome P450 monooxygenases is the most important in insects. Resistance to insecticides caused by enhanced microsomal monooxygenase activities has been reported in numerous insects. 

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