TABLE 2

Enzyme kinetic parameters of buspirone metabolism in HLM [¹⁴C]Buspirone, at concentrations ranging from 2.5 to 150 μM, was incubated with pooled human liver microsomes (0.1 mg/ml) and NADPH (500 μM) in 100 mM sodium phosphate buffer (pH 7.4) for 5 min. Data presented in this table were averaged from analyses of duplicate incubations.

Metabolic Reaction	Apparent K_m	Apparent V_max	Apparent CL_int
	μM	nmol/min/mg protein	ml/min/mg protein
1-PP formation	8.7 ± 1.1	0.74 ± 0.02	0.085
3′-OH-Bu formation	4.3 ± 0.8	0.30 ± 0.01	0.070
6′-OH-Bu formation^a	8.8 ± 0.9	1.37 ± 0.04	0.156
5-OH-Bu formation^a	11.4 ± 5.6	0.77 ± 0.25	0.068
	514 ± 231	7.5 ± 2.2	0.015
Bu N-oxide formation	34.0 ± 8.9	1.64 ± 0.8	0.048

↵ a Kinetic plots of the formation of the metabolite are presented in Fig. 4