Enzyme Kinetics
Michaelis–Menten saturation and competitive inhibition
An enzyme has two regimes: substrate-limited and saturated. Drag V_max and K_m to see the curve shift; add a competitive inhibitor and watch the apparent K_m grow while V_max stays pinned. Saturation always wins at high substrate — that is what makes the inhibition competitive.
v([S]) no inhibitorv([S]) with competitive inhibitor
Vmax
100.0
Km
5.00
Kmapp = Km(1 + [I]/Ki)
5.00
v = Vmax[S] / (Km + [S]). A competitive inhibitor raises the apparent Km and leaves Vmax untouched — saturation still wins at high substrate. Noncompetitive inhibition lowers Vmax; that is a different curve.