Enzyme Inhibition Visualizer
Visualize competitive, noncompetitive, and uncompetitive enzyme inhibition with interactive Michaelis-Menten and Lineweaver-Burk plots.
Important: This tool uses simplified models for educational purposes only. It does not design inhibitors, predict drug efficacy, or provide therapeutic guidance. Not for clinical or diagnostic use.
Results
Enter enzyme kinetic parameters and select an inhibition type to visualize Michaelis-Menten and Lineweaver-Burk plots comparing uninhibited and inhibited enzyme activity.
Understanding Enzyme Inhibition Kinetics
Michaelis-Menten Kinetics
The Michaelis-Menten equation describes the relationship between reaction velocity (v) and substrate concentration ([S]) for many enzyme-catalyzed reactions:
Vmax is the maximum reaction velocity when the enzyme is saturated with substrate. Km (Michaelis constant) is the substrate concentration at which the reaction rate is half of Vmax. A lower Km indicates higher substrate affinity.
The Inhibition Factor (α)
Enzyme inhibition is quantified using the inhibition factor α:
Where [I] is the inhibitor concentration and Ki is the inhibition constant. A lower Ki indicates tighter inhibitor binding and stronger inhibition. When α = 1, there is no inhibition. As α increases, inhibition becomes more pronounced.
Types of Reversible Inhibition
Competitive Inhibition
The inhibitor competes with the substrate for binding to the enzyme's active site. The inhibitor can only bind to free enzyme (E), not to the enzyme-substrate complex (ES).
Effect: Apparent Km increases (Km' = Km × α), but Vmax remains unchanged. Inhibition can be overcome by increasing [S].
Km' = Km × α
Vmax' = Vmax
Noncompetitive Inhibition
The inhibitor binds to a site other than the active site (allosteric site). It can bind to both free enzyme (E) and enzyme-substrate complex (ES) with equal affinity.
Effect: Vmax decreases (Vmax' = Vmax / α), but Km remains unchanged. Cannot be overcome by increasing [S].
Km' = Km
Vmax' = Vmax / α
Uncompetitive Inhibition
The inhibitor binds only to the enzyme-substrate complex (ES), not to free enzyme. Binding of substrate actually promotes inhibitor binding.
Effect: Both Km and Vmax decrease by the same factor α. The ratio Km/Vmax remains constant.
Km' = Km / α
Vmax' = Vmax / α
Lineweaver-Burk Plot
The Lineweaver-Burk plot (double-reciprocal plot) linearizes the Michaelis-Menten equation, making it easier to determine kinetic parameters and distinguish between inhibition types:
Y-intercept
1/Vmax
X-intercept
-1/Km
Slope
Km/Vmax
Identifying Inhibition Type from Lineweaver-Burk Plots
| Inhibition Type | Y-intercept (1/Vmax) | X-intercept (-1/Km) | Pattern |
|---|---|---|---|
| Competitive | Same | Different | Lines intersect on Y-axis |
| Noncompetitive | Different | Same | Lines intersect on X-axis |
| Uncompetitive | Different | Different | Parallel lines (same slope) |
Limitations of This Model
- Steady-state assumption: Model assumes [ES] is constant during measurement
- Simple inhibition: Does not model mixed inhibition, allosteric enzymes, or cooperativity
- Reversible binding: Only applies to reversible inhibitors, not irreversible inactivators
- Single substrate: Model is for single-substrate reactions; multi-substrate kinetics are more complex
- Idealized conditions: Real enzyme behavior depends on pH, temperature, ionic strength, etc.
Important Disclaimer
This tool provides simplified visualizations for educational purposes only. It does NOT design inhibitors, predict drug efficacy, or provide therapeutic guidance. Actual enzyme kinetics experiments require proper controls, statistical analysis, and validation. Always consult experts for drug development, enzymology research, or clinical applications.
Frequently Asked Questions
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