Free Enzyme Inhibition Calculator

Calculate apparent kinetic parameters under competitive or noncompetitive enzyme inhibition.

umol/min
uM
uM
uM
uM

Velocity (Competitive Inhibition)

25.00 umol/min

Apparent Km (Competitive)150.00 uM
Velocity (Noncompetitive Inhibition)16.67 umol/min

Velocity (Competitive Inhibition) vs Substrate Concentration [S]

Enzyme Inhibition Types

Competitive Inhibition

Inhibitor binds to the active site, increasing apparent Km while Vmax remains unchanged.

v = Vmax × [S] / (alpha × Km + [S]), where alpha = 1 + [I]/Ki

Noncompetitive Inhibition

Inhibitor binds away from the active site, decreasing apparent Vmax while Km remains unchanged.

v = (Vmax/alpha) × [S] / (Km + [S])

Competitive inhibition can be overcome by high substrate concentration; noncompetitive cannot.

Example Calculation

Vmax=100, Km=50 uM, [I]=20 uM, Ki=10 uM, [S]=50 uM.

  1. 01alpha = 1 + 20/10 = 3.0
  2. 02Competitive: v = 100 × 50 / (50 × 3 + 50) = 5000 / 200 = 25.0 umol/min
  3. 03Noncompetitive: v = (100/3) × 50 / (50 + 50) = 33.33 × 0.5 = 16.67 umol/min

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