Enzymatic Degradation of Deltamethrin

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.