TABLE 2

T₁ relaxation rate-estimated distances of flurbiprofen protons from the heme iron of CYP2C9.1 in the absence and presence of 300 nM benzbromarone

Errors for measurements are shown within parentheses. Errors in the T₁ values were those reported by the fitting routine. Errors in the reported distances (r) were determined by propagation of error from the T₁ calculation. Flurbiprofen concentration was 145 μM; benzbromarone concentration was 300 nM when studied together. See Fig. 1 for the numbering scheme of the flurbiprofen protons. T₁ calculations for the HC-CO₂H proton could not be accurately determined because of interference from the residual glycerol resonances. T₁ values are in seconds. [P450 2C9] = 0.014 μM; α_M = [P450]/(K_s + [substrate]), K_s (flurbiprofen) = 7.8 μM, α_M (flurbiprofen) = 9.16 × 10⁻⁵. Distance values are in angstroms (Å), r = C[T_1P × α_M × f(τ_c)]^−1/6, C = 539 (Mildvan and Gupta, 1978), 1/T_1P = 1/T_{1, 2C9} − 1/T_{1, 2C9 + CO} (Mildvan and Gupta, 1978), f(τ_c) = 2 × 10⁻¹⁰ s⁻¹.