TABLE 2

Kinetic parameters for flutamide hydrolase activities by recombinant AADAC and tissue microsomes

Data represent the mean ± S.D. of triplicate determinations. CL_int values of human AADAC and MLM are expressed as V_max/K_m.

Species	K_m or S₅₀^{^a}	V_max	CL_int or CL_max^{^b}	K_i	n
	mM			μM
Human
AADAC	0.6 ± 0.1	1.1 ± 0.1^{^c}	1.7 ± 0.0^{^d}
Liver	1.1 ± 0.0	1.9 ± 0.1^{^e}	1.8 ± 0.1^{^f,^g}
Jejunum	0.2 ± 0.1^{^h}	1.9 ± 0.6^{^e,^h}	12.9 ± 0.3^{^f,^g}	14.0 ± 5.6^{^h}
	4.7 ± 2.1^ⁱ	7.8 ± 3.0^{^e,ⁱ}
Kidney	2.1 ± 0.1^{^h}	3.8 ± 0.2^{^e,^h}	1.2 ± 0.0^{^f,^g}	0.6 ± 0.1^{^h}
Lung	N.D.	N.D.	N.D.
Rat
AADAC	5.1 ± 0.6	4.7 ± 0.5^{^c}	1.0 ± 0.0^{^d,^f}
Liver	1.0 ± 0.0^{^a}	2.9 ± 0.3^{^e}	1.4 ± 0.1^{^b,^g}		1.8 ± 0.1
Jejunum	4.2 ± 0.2^{^a}	1.7 ± 0.1^{^e}	0.2 ± 0.0^{^b,^g}		1.4 ± 0.1
Kidney	5.8 ± 0.4^{^a}	2.7 ± 0.2^{^e}	0.2 ± 0.0^{^b,^g}		1.5 ± 0.0
Lung	0.7 ± 0.0^{^a}	0.1 ± 0.0^{^e}	0.1 ± 0.0^{^b,^g}		2.1 ± 0.1
Mouse
AADAC	3.5 ± 0.0	3.7 ± 0.1^{^c}	0.9 ± 0.0^{^d,^f}
Liver	7.3 ± 0.6	9.1 ± 0.6^{^e}	1.2 ± 0.0^{^f,^g}
Jejunum	0.5 ± 0.0	0.1 ± 0.0^{^e}	0.2 ± 0.0^{^g}
Kidney	0.8 ± 0.1	0.4 ± 0.0^{^e}	0.6 ± 0.0^{^f,^g}
Lung	0.4 ± 0.0^{^a}	0.0 ± 0.0^{^e}	0.0 ± 0.0^{^b,^g}		5.2 ± 1.2

n, Hill coefficient; N.D., not determined.
↵a S₅₀ value calculated by the Hill equation.
↵b CL_max value calculated by the Hill equation.
↵c V_max for AADAC is measured in nmol · min⁻¹ · unit⁻¹.
↵d CL_int or CL_max for AADAC is measured in μl · min⁻¹ · unit⁻¹.
↵e V_max for liver, jejunum, kidney, and lungs is measured in nmol · min⁻¹ · mg⁻¹.
↵f If the K_m values were relatively high, CL_int values were calculated with the initial slope of the velocity versus substrate concentration. CL_max values were calculated with the following equation: V_max × (n − 1)/[S₅₀ × n × (n − 1)^1/ⁿ].
↵g CL_int or CL_max for liver, jejunum, kidney and lungs is measured in μl · min⁻¹ · mg⁻¹.
↵h Value calculated by the substrate inhibition equation.
↵i Value calculated by the Michaelis-Menten equation.