This applet demonstrates kinetics of an enzyme acting on two substrates. Click on the Start button to plot reaction velocity (V) against substrate A concentration ([SA]) [left hand graph panel], and to show their double reciprocals in a Lineweaver-Burk plot (1/V versus 1/[SA]) at different fixed concentrations of substrate B [right graph panel].

Apparent V_maxs are equal to the reciprocals of the intercepts on the 1/V axis of the regression lines in the right graph panel. Apparent K_ms are equal to the slopes of the regression lines divided by the corresponding intercepts on the 1/V axis of the regression lines in the right graph panel. The curves drawn through the data points in the left graph panel are obtained by substituting apparent V_maxs and corresponding apparent K_ms in the Michaelis-Menten equation:

Colors refer to different concentrations of substrate B (SB1 = 10 mM --- BLACK; SB2 = 2 mM --- RED; SB3 = 1 mM --- BLUE; SB4 = 0.5 mM --- GREEN; SB5 = 0.3 mM --- MAGENTA).