TABLE 4

Tolbutamide metabolism by the recombinant mouse CYP2Cs Recombinant mouse P450 proteins were expressed in E. coli and partially purified as described under Materials and Methods. The purified proteins were reconstituted with phospholipids, and tolbutamide metabolism ([ring-U-¹⁴C]tolbutamide) was measured as described under Materials and Methods. Detection limit for the assay was <0.5 nmol/min/nmol P450. Values represent the means ± S.E. of three samples. The turnover number for CYP2C9 is 4.39 ± 0.023 nmol/min/nmol P450.