Initial velocities of Gt activation by photoactivated bvRh (A) and mG (B) in POPC/POPG, POPC, and DOPC/POPG nanodiscs. Initial velocities of bvRh and mG in POPC/POPG, POPC, and DOPC/POPG nanodiscs (closed squares, closed circles, and closed triangles, respectively) at 37 °C were plotted against Gt concentration and fitted by the Michaelis-Menten equation or Equation 29 (solid lines for POPC/POPG nanodiscs, dashed lines for POPC nanodiscs, and dotted lines for DOPC/POPG nanodiscs) to estimate Vmax/R*. Error bars represent S.D. estimated from three independent measurements.