How do you convert hydrodynamic (Stokes) radius to molecular weight?

Published on June 30th, 2021

Hydrodynamic, or Stokes, radius of a particle is the radius of a hard sphere that diffuses at the same rate as that particle. When we are considering proteins, they are of course not hard particles, but complex folds of varying compactness and shape. The hydrodynamic radius of a peptide chain can thus vary depending on its folding state. For this reason, when converting hydrodynamic radius to molecular weight we can provide approximate boundaries corresponding to a fully folded, globular peptide in its most compact state, and a fully unfolded chain that has the least compact state.

We’ve created a converter to enable you to make this conversion for both folded and unfolded proteins—from hydrodynamic radius to molecular weight or vice versa. Simply choose which state you expect the protein to be in and update the values accordingly.