Functional Significance of Cytochrome P450 1A2 Allelic Variants, P450 1A2*8, *15, and *16 (R456H, P42R, and R377Q)

摘要: P450 1A2 is responsible for the metabolism of clinically important drugs and metabolic activation environmental chemicals. Genetic variations can influence its ability to perform these functions, thus, this study aimed characterize functional significance three allelic variants containing nonsynonymous single nucleotide polymorphisms (P450 1A2*8, R456H; *15, P42R; *16, R377Q). Variants SNPs were constructed recombinant enzymes expressed purified in Escherichia coli. Only P42R variant displayed typical CO-binding spectrum indicating a holoenzyme with an expression level ∼ 170 nmol per liter culture, but no spectra observed two other variants. Western blot analysis revealed that was lower than wild type, however R456H R377Q not detected. Enzyme kinetic analyses indicated mutation resulted significant changes catalytic activities. The increased turnover numbers (kcat) both methoxyresorufin O-demethylation phenacetin O-deethylation. In case O-deethylation analysis, overall efficiency (kcat/Km) up 2.5 fold slight increase Km value. This substitution N-terminal proline-rich region contributed improvement activity albeit reduction structural stability or decrease substrate affinity. Characterization should be carefully examined terms many clinical