Addition of BrPy to H441 cells reduced total hexokinase activity in cell extracts in a dose-dependent manner with an IC50 of 1.2 ± 0.28 mM (Fig. 2A). The data did not follow a classic sigmoid curve, and there was an indication that the inhibition was biphasic. We were unable to unambiguously fit such a curve to the data. However, the IC50 obtained from the initial inhibition of hexokinase activity was lower at 0.04 ± 0.01 mM. As there was no statistical difference in hexokinase activity between pretreatment with 100 µM and pretreatment with 1 mM, it was decided to use the lower concentration of BrPy. At this concentration, total cellular hexokinase activity was reduced by 25.1 ± 11.6% in H441 cells cultured at air-liquid interface (n = 6 experiments; Fig. 2B).