What is hydrodynamic radius?

The hydrodynamic radius is a measure of the effective size of a molecule or particle in a fluid or solution, taking into account both the molecular weight and shape of the molecule. It is often used in the field of biochemistry and biophysics to characterize the size and shape of macromolecules such as proteins and nucleic acids.

The hydrodynamic radius is determined experimentally using techniques such as gel filtration chromatography, dynamic light scattering, and sedimentation velocity analysis. It is defined as the radius of a hypothetical sphere that diffuses at the same rate as the molecule in the solution.

The hydrodynamic radius is influenced by various factors, including the molecular weight, shape, charge, and interactions with other molecules in the solution. For example, molecules with a larger hydrodynamic radius tend to diffuse more slowly in a solution compared to smaller molecules.

Overall, the hydrodynamic radius provides important information about the size and behavior of molecules in solution, which is crucial for understanding their biological functions and interactions.