1. Estimation of Vmax and K by Inspection Although graphical methods are available for accurate determination of the Vmax and Km of an enzyme-catalyzed reaction (see Box 6-1), sometimes these quantities can be quickly estimated by inspecting values of V, at increasing [S]. Estimate the Vmax and Km of the enzyme-catalyzed reaction for which the following data were obtained. [S] (M) 2.5 × 10 Vo (m/min) (W) [S] 28 4 x 10-5 Vo (m/min) 112 4.0 × 10- 40 1 × 10-4 128 1 x 10-5 70 2 x 10-3 139 2 x 10-5 95 1 x 10-2 140 2. Relation between Reaction Velocity and Substrate Concentration: Michaelis-Menten Equation (a) At what substrate concentration would an enzyme with a keat of 30.0 s¹ and a Km of 0.0050 M operate at one-quarter of its maximum rate?