Binding affinity between BF211 and the proteasome β subunits. (A) Results of a preliminary experiment examining the binding affinity of BF211 (1 and 10 μmol/L) to the recombinant proteasome β1, β2 and β5 subunit proteins. (B) Real-time binding affinity measurements of 2.40, 3.43, 4.9, 7, 10 and 20 μmol/L BF211 with the recombinant proteasome β1 subunit protein. (C) Proteasome activities in cell lysate incubated in vitro with various concentrations of BF211 or bortezomib (positive control). Data are presented as the mean±SEM. n=3 independent experiments. *P<0.05 vs the solvent control.