Ligand-binding kinetics

Ligand Binding Kinetics

Change the on-rate, off-rate, and ligand concentration. Watch receptors bind and unbind in real time, compare the measured occupancy with the equilibrium prediction, and see how kinetics and affinity are related.

On-rate k_on 0.20

Off-rate k_off 0.20

Ligand concentration [L] 1.00

Measured bound fraction

0.00

Predicted equilibrium θ

0.50

Affinity K_D = k_off/k_on

1.00

Relaxation time τ

2.50

Single Receptor and Occupancy Trace

Ensemble Occupancy

Bound Fraction in Time

Main idea Equilibrium occupancy depends on affinity and ligand concentration. The approach to equilibrium depends on the overall rate k_on[L] + k_off.