TABLE 2

Inhibitory parameters of short-chain CoQ analogs on DOXol and DNRol formation by human heart cytosolic fractions

Experiments were performed by incubating cytosolic fractions (1 mg protein/ml) in standard buffer at 37°C with or without (vehicle) different concentrations of each short-chain CoQ analog added 5 minutes before DOX or DNR (50 μM, final concentration). Reactions were started by adding NADPH (250 μM, final concentration). Alcohol metabolites were assayed after 240 minutes at 37°C as described in Materials and Methods. Values are the mean ± S.E. of three separate experiments performed in triplicate. The IC50 values are determined as described in Materials and Methods.

CompoundDOXDNR
IC50ImaxIC50Imax
μM%μM%
CoQ011.5 ± 0.6103.6 ± 1.710.1 ± 1.2100.9 ± 0.6
CoQ1151.5 ± 9.398.7 ± 3.877.8 ± 5.1102.1 ± 3.0
CoQ2N.D.N.D.93.5 ± 7.4103.0 ± 4.1
DB198.9 ± 8.6102.3 ± 5.4150.7 ± 9.0101.1 ± 4.2
IDB94.3 ± 6.799.4 ± 4.158.5 ± 4.498.3 ± 2.8
IDB plus Dicumarol (20 μM)27.0 ± 1.798.7 ± 3.321.6 ± 3.2101.7 ± 0.9
  • DB, decylubiquinone; N.D., not determinable.