TABLE 2

Kinetic parameters of thioridazine metabolism in cDNA-expressed human P450s (Supersomes)

P450
Thioridazine Mono-2-sulfoxidation
Thioridazine Di-2-sulfoxidation
Thioridazine 5-Sulfoxidation
Thioridazine N-Demethylation
Km
Vmax
Vmax/Km
Km
Vmax
Vmax/Km
Km
Vmax
Vmax/Km
Km
Vmax
Vmax/Km
μM pmol/mg protein/min μM pmol/mg protein/min μM pmol/mg protein/min μM pmol/mg protein/min
CYP1A2 160 1.786 0.0112 16 0.020 0.0012 80 7.519 0.0940 36 0.403 0.0112
CYP2A6 323 0.485 0.0015 48 0.004 0.0001 34 0.879 0.0258 200 0.200 0.0010
CYP2B6 67 0.605 0.0090 55 0.006 0.0001 71 1.412 0.0199 55 0.124 0.0022
CYP2C9 45 0.221 0.0049 91 0.009 0.0001 114 1.250 0.0110 20 0.057 0.0028
CYP2C19 47 6.289 0.1338 26 0.141 0.0054 800 6.993 0.0087 400 2.128 0.0053
CYP2D6 62 16.667 0.2688 10 0.468 0.0468 385 5.263 0.0137 67 0.233 0.0035
CYP2E1 333 0.527 0.0016 38 0.004 0.0001 50 1.160 0.0232 83 0.109 0.0013
CYP3A4
42
0.302
0.0072
20
0.009
0.0004
28
1.193
0.0426
21
0.148
0.0070

  • The highest intrinsic clearances are shown in bold.