Fluorescence Anisotropy Calculator
Calculate fluorescence anisotropy and polarization for molecular dynamics studies
Intensity Measurements
Correction for instrument polarization bias
Physical Parameters
Anisotropy (r)
0.1818
Polarization (P)
0.2500
Calculated Parameters
Total Intensity110,000
Rotational Corr. Time (θ)3.434 ns
Theoretical Anisotropy0.1848
Depolarization Factor2.16
Equations
r = (I∥ - GI⊥) / (I∥ + 2GI⊥)
P = (I∥ - GI⊥) / (I∥ + GI⊥)
r = r₀ / (1 + τ/θ)
Interpretation
Intermediate anisotropy - partial binding or medium-sized complex
About Fluorescence Anisotropy
Fluorescence anisotropy measures the rotational diffusion of fluorescent molecules, which is related to molecular size and binding state.
- Free ligand: Fast rotation, low anisotropy (r ~ 0.02-0.05)
- Bound to protein: Slow rotation, high anisotropy (r ~ 0.15-0.35)
- Applications: Binding assays, drug screening, protein-protein interactions
- Limiting anisotropy (r₀): Typically 0.3-0.4 for most fluorophores