Partial characterization of soluble esterase from Heterodera glycines and inhibition by aldicarb and phenamiphos.
1. Homogenates of tissues from females of the nematode Heterodera glycines were clarified by centrifugation and used to initiate characterization of soluble esterases using p-nitrophenyl acetate as the substrate. 2. Optimum temperature and pH were 40 degrees C and 7.2 respectively. 3. Acetazolamide (a carbonic anhydrase inhibitor) at 10(-3) M did not inhibit enzyme activity, indicating that carbonic anhydrase was not present. 4. Phenamiphos (an organophosphate) at 10(-6) M reduced activity by 38%, whereas eserine hemisulfate (a cholinesterase inhibitor) and aldicarb (a carbamate) were not inhibitory at that concentration, indicating that there was no cholinesterase activity. 5. Eserine hemisulfate, aldicarb, and phenamiphos inhibited enzyme activity by 50% (I50) at 5 x 10(-3) M, 7.5 x 10(-4) M, and 6 x 10(-6) M, respectively. 6. Approximately 25% of the activity detected appeared due to A- and/or C-esterases. 7. The data demonstrated that aldicarb and phenamiphos were active against esterases other than acetylcholinesterase.
University of Illinois, Urbana 61801.
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D000086:Acetazolamide / Q000494:pharmacology; D000448:Aldicarb / Q000494:pharmacology*; D000818:Animals; D004950:Esterases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007306:Insecticides / Q000494:pharmacology*; D009348:Nematoda / Q000201:enzymology*; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D010830:Physostigmine / Q000494:pharmacology; D013696:Temperature
D007306:Insecticides; D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008642:4-nitrophenyl acetate; D000448:Aldicarb; D010830:Physostigmine; D004950:Esterases; C002698:fenamiphos; D000086:Acetazolamide