Table 1.

Kinetic parameters of dithionite-dependent reduction of the total pool and the high-spin fraction of CYP3A4 in various systems at no substrate added and in the presence of bromocriptine.^*

		Total CYP3A4						High-spin fraction
System	Bromocriptine, μM	k1 s−1	k2 s−1	k3 s−1	F1	F2	F3	kfast, s−1	kslow, s−1	Fslow
Oligomers in solution	0	3.3 ± 0.6	0.41 ± 0.07	0.081 ± 0.01	0.33 ± 0.07	0.35 ± 0.05	0.32 ± 0.05	0.48 ±0.17	0.074 ±0.02	0.83 ±0.10
	32	3.5 ± 0.4	0.23 ± 0.10	0.043 ± 0.02	0.06 ± 0.02	0.37 ± 0.06	0.58 ± 0.07	0.29 ±0.12	0.043 ±0.02	0.71 ±0.13
Monomers (0.15% Emulgen-913)	0		0.44 ± 0.01			1.0		0.56 ±0.17		0
	24		0.37 ± 0.01			1.0		0.47 ±0.03		0
Nanodisc- incorporated CYP3A4	0	6.2 ± 0.6		0.59 ± 0.14	0.84 ± 0.03		0.16 ± 0.03	6.2 ± 0.6	0.72 ±0.30	0.3 ±0.10
	24	4.4 ± 1.8		0.14 ± 0.01	0.03 ± 0.07		0.97 ± 0.07		0.11 ±0.01	1.0
P450-rich proteoliposomes (Sample I)	0	8.8 ± 1.6	2.2 ± 0.2	0.20 ± 0.05	0.22 ± 0.09	0.52 ± 0.09	0.25 ± 0.07	1.9 ±0.5	0.14 ±0.06	0.7 ±0.16
	6	3.9 ± 0.1	0.92 ± 0.42	0.12 ± 0.01	0.11 ± 0.01	0.21 ± 0.05	0.66 ± 0.13		0.10 ±0.01	1.0
Lipid-rich proteoliposomes (Sample II)	0	2.0 ± 0.1			1.0			1.9 ± 0.1		0
	32			0.050 ± 0.02			1.0		0.045 ±0.01	1.0

^*The values given in the Table were obtained by averaging the result of 3–12 individual measurements and the “±” values show the confidence interval calculated for p = 0.05.