Ki to IC50 Converter

What is Ki to IC50 Conversion?

Ki to IC50 conversion uses the Cheng-Prusoff equation to interconvert between inhibition constant (Ki) and half-maximal inhibitory concentration (IC50) for competitive enzyme inhibition. This is essential for pharmacological and biochemical analysis.

How to Use This Ki IC50 Converter

Simple 3-step process:

1. Select conversion direction (Ki→IC50 or IC50→Ki)
2. Enter input value, substrate concentration [S], and Km
3. View calculated result automatically

When to Use

This converter is useful when you need to:

• Compare inhibitor potencies across different assay conditions
• Convert literature Ki values to IC50 for your experimental setup
• Standardize inhibition data from different substrate concentrations
• Design dose-response experiments for drug discovery

Example Input

Sample enzyme inhibition data:

Try with your own inhibition parameters or use the Example button.

Example Output

Converted inhibition value:

Results show both converted value and relationship between parameters.

FAQ

Q: What is the Cheng-Prusoff equation?
A: IC50 = Ki × (1 + [S]/Km) for competitive inhibition, relating IC50 to Ki based on substrate concentration and Km.

Q: When is this equation valid?
A: For competitive inhibition only. Non-competitive inhibition follows different relationships.