The combination of the viscosity increment with the harmonic mean rotational relaxation time for determining the conformation of biological macromolecules in solution.

A new hydrodynamic shape function, lambda, is derived for determining the conformation of biological macromolecules in solution, adding to the increasing number of shape parameters whose experimental determination does not require a knowledge of the particle swelling due to solvation in solution. lambda can be found from a knowledge of the molecular weight, intrinsic viscosity and the harmonic mean rotational relaxation time. A table of values and a plot of lambda as a function of axial ratio for both oblate and prolate ellipsoids of revolution are given.