Figure 3: Cell-membrane permeability of AkaLumine-HCl.

(a) Cell-membrane permeability of the substrates. Ratio of bioluminescence (BL) intensity indicates relative bioluminescence intensity of intact cells versus lysed cells treated with indicated substrates at 2.5 μM. n=3, *P<0.05 (t-test). (b) BL production in LLC/luc cells with or without pretreatment with 0.1% Triton X-100 (TX). BL intensity was measured every 10 s after addition of CycLuc1 or AkaLumine-HCl (Aka-HCl) (final concentration of 25 μM). BL intensity at each time point was normalized to the peak intensity. n=3. (c) BL production with recombinant Fluc protein. The substrates (final concentration of 25 μM) were reacted with recombinant Fluc proteins (20 μg ml⁻¹). The reaction was initiated by the addition of ATP-Mg (final concentration of 80 μM). Data are representative of three independent experiments. Error bars indicate s.e.m.