Table 2

Kinetic parameters for 5-FU formation from tegafur by human liver microsomes

Human Liver Microsomes	K_m	V_max	V_max/K_m
	mM	nmol/min/mg protein	ml/min/mg protein
HL-9	1.72 ± 0.39	0.45 ± 0.06	0.26
HG3	0.95 ± 0.11	0.75 ± 0.04	0.79
HG30	1.87 ± 0.12	1.13 ± 0.04	0.60

Kinetic analyses for 5-FU formation from tegafur were determined with human liver microsomes (0.5 mg of protein/ml) and substrate concentrations between 25 μM and 2 mM. The kinetic parameters were calculated from the fitted curves using the computer program KaleidaGraph.