Table 1.

Binding affinities to Bcl-2 family proteins

FPA Ki (nmol/L)TR-FRET Ki (nmol/L)
Bcl-xLBcl-2Bcl-wMcl-1 *A1 *Bcl-xL
hBad0.5 ± 0.115 ± 422 ± 10>1,000>1,0000.12
hNoxa>1,000>1,000>1,00064 ± 6107 ± 43>93
ABT-737≤0.5<10.9>10000.08
ABT-263≤0.5≤1≤1550 ± 40354 ± 630.40
Enantiomer3 ± 2≤179 ± 17370 ± 90444 ± 1217.4
  • NOTE: Binding affinity of ABT-263, its enantiomer, ABT-737, Bad-BH3 (Ac-NLWAAQRYGRELRRMSDK(FITC)FVD-amide, and Noxa-BH3 (6-FAM-GELEVEFATQLRRFGDKLNF-amide) for Bcl-2 family proteins. Shown is the Ki ± SE (n ≥ 3). For TR-FRET, shown is the mean Ki (n = 2).

    Abbreviations: FPA, fluorescence polarization assay; TR-FRET, time-resolved fluorescence resonance energy transfer assay.

  • * IC50 values reported for Mcl-1 and A1.