FIGURE 3.

ATP‐initiated kinetics of helicases from Sulfolobus tokodaii (StXPB2) and Archaeoglobus fulgidus helicases (AfXPB). (a) Normalized square wave voltammetry (SWV) peak current versus time after ATP addition for electrochemically active DNA monolayers treated with two concentrations of StXPB2 helicase. (b) Normalized SWV peak current versus time after ATP addition for electrochemically active DNA monolayers treated with two different concentrations of AfXPB helicase. (Inset: normalized SWV peak current vs. time for the 200 nM AfXPB sample over the first 30 s.) Symbols indicate the data and solid curves are first‐order exponential decay fits to the data, and decay times are presented as average ± standard error of the mean for at least three trials.