The recombinant CYP6A14 and CYP6N6 proteins were tested in an in vitro nicotinamide adenine dinucleotide phosphate regeneration system to determine their deltamethrin degradation ability. The reaction system in 2 mL PBS (pH, 7.4) consisted of 1 mM glucose-6-phosphate dehydrogenase, 1 mM glucose 6-phosphate, 0.25 mM MgCl2, 0.1 mM NADP+, 1 mg/L deltamethrin, and 50 mg/L recombinant protein CYP6A14/CYP6N6. The reaction was performed at 30°C and 200 rpm for 5, 10, 30, and 60 minutes. Finally, the reaction was terminated by incubating with 100 μL methanol (chromatographic grade) for 5 minutes. The reaction without the recombinant protein was used as a blank control. The samples were centrifuged at 12,000 rpm and 4°C for 15 minutes. The obtained supernatants were used to measure the concentration and degradation products of deltamethrin by gas chromatography–tandem mass spectrometry (GC-MS/MS) using a C18 column. The conditions were as follows: sample size, 1 μL; column temperature, 30°C; flow rate, 0.3 mL/minute; mobile phase composition, distilled water, 0.1% formic acid, and chromatographic pure acetonitrile; injection volume, 2 μL; and automatic injection temperature, 4°C.
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