We report measurements of the osmotic susceptibility and mutual diffusion coefficient of solutions of charged bovine albumin molecules made using laser serum light scattering. The measurements were made as a function of solution ionic strength for various macromolecular charge states ranging from-4e to-13e. We find that the osmotic susceptibility data may be interpreted quantitatively in terms of the simple Verwey-Overbeek interaction potential, provided that adequate is care taken in computing the radial distribution function. Current theoretical treatments of the dynamics, with hydrodynamicinteractions included to first order in the concentration, are found to deviate significantly K50%) from the diffusion coefficient data. The deviations occur under all conditions of charge and ionic strength for which the susceptibility has been reduced to less than half the ideal gas value