TABLE 2

Parameters for steady-state metabolism of styrene by CYP2E1

The nonsymmetrical 95% confidence intervals for parameters are shown in parentheses.

Enzyme System	Parameters for Hill Equation			Parameters for Allosteric Model^{^a}
Enzyme System	V_max^{^b}	Hill Slope (n)	S₅₀	V_max^{^b}	K_s	K_ss
			μM		μM
Recombinant CYP2E1	6.7 (5.9–7.4)	1.5 (1.2–1.9)	270 (210–330)	6.3 (5.9–6.9)	830 (500–3700)	110 (16–350)
HLM 150^{^c}	0.79 (0.65–0.92)	1.6 (1.2–2.0)	110 (80–140)	0.74 (0.69–0.84)^{^c}	375 (210–3500)	39 (2.8–140)

↵a See Fig. 2. For HLM 150, data were fit from 0 to 350 μM styrene.
↵b Units are nmol · min⁻¹ · nmol⁻¹ for recombinant CYP2E1 or nmol · min⁻¹ · mg protein⁻¹ for HLM 150.
↵c Ninety percent confidence intervals were used for analysis of the HLM 150 discrimination.