Table 2.

Spectral titration of human P450 2C8, and 2C9 with fatty acids

Fatty acid	P450 2C8		P450 2C9
	ΔAmaxa	Ksb (μM)	ΔAmax	Ks (μM)
C14:0	0.051 ± 0.001c	8.0 ± 0.7c	0.040 ± 0.002	13 ± 2
C16:0	0.044 ± 0.002	1.5 ± 0.6	0.055 ± 0.004	11 ± 2
C16:1	0.041 ± 0.003	7.9 ± 1.8	0.056 ± 0.005	8.7 ± 1.8
C18:1	0.027 ± 0.002	1.1 ± 0.7	0.046 ± 0.005	6.8 ± 2.1
C18:2	0.046 ± 0.003	0.5 ± 0.3	0.045 ± 0.002	0.8 ± 0.3
C20:4	0.062 ± 0.005	13 ± 3.0	0.037 ± 0.002	0.5 ± 0.3
C22:6	–d	–	0.042 ± 0.005	9.3 ± 2.6

^aDifference in absorbance between the wavelength maximum at 390 nm and minimum at 420 nm, ΔA₃₉₀ – A₄₂₀. The concentration range used was 0 to 50 μM fatty acid in each case.

^bEstimated from the hyperbolic fitting plot of ΔA_max versus the fatty acid concentration.

^cData presented in Supporting Information Figure S-2.

^d–, no detectable binding (ΔA₃₉₀ < 0.005 at 50 μM).