ΔG to Kd Converter

Convert between Gibbs free energy (ΔG) and dissociation constant (Kd) using thermodynamic equations for binding affinity analysis.

ΔG → Kd

°C
Kd = -
Enter ΔG value to see binding affinity interpretation
Kd = e^(ΔG/RT)

Kd → ΔG

°C
ΔG = -
Enter Kd value to see thermodynamic interpretation
ΔG = RT ln(Kd)

What is ΔG to Kd Conversion?

The ΔG to Kd converter calculates the relationship between Gibbs free energy (ΔG) and dissociation constant (Kd) using fundamental thermodynamic equations. This conversion is essential for understanding binding affinity in molecular interactions, particularly protein-ligand binding.

How to Use This Converter

Easy thermodynamic conversion:

  1. Enter ΔG value with units (kJ/mol or kcal/mol) to get Kd
  2. Or enter Kd value with units (M, mM, μM, nM, pM) to get ΔG
  3. Adjust temperature (default 25°C = 298.15K)
  4. View binding affinity interpretation and formula

When to Use

This converter is useful for:

  • Analyzing protein-ligand binding studies
  • Converting between thermodynamic and kinetic parameters
  • Interpreting binding affinity measurements
  • Drug discovery and molecular design research
  • Comparing binding strengths across different systems

Example Input

Sample conversion:

ΔG = -25.0 kJ/mol at 25°C
Kd = 100 nM at 25°C

Try the Example button for typical protein-ligand values.

Example Output

Conversion results show:

Kd = 2.48 × 10⁻⁷ M (248 nM)
ΔG = -25.0 kJ/mol
Binding: Moderate affinity

Includes binding strength interpretation and calculation formula.

FAQ

Q: What's the relationship between ΔG and Kd?
A: ΔG = RT ln(Kd), where R is gas constant and T is temperature in Kelvin.

Q: What does negative ΔG mean?
A: Negative ΔG indicates favorable binding (low Kd = high affinity).

Q: How does temperature affect the conversion?
A: Higher temperature increases RT, affecting the ΔG-Kd relationship proportionally.