Sedimentation studies on haemoglobin in water gave a sedimentation constant S = 4.5 Sv at 20°C. The diffusion coefficient is 6.3 x 10-11 m2 S-1 at the same temperature. Calculate the molar mass of haemoglobin using Vs = 0.75 cm g-I for its partial specific volume and p = 0.998 g cm-1 for the density of the solution. Estimate the effective radius of the haemoglobin molecule given that the viscosity of the solution is 1.00 x 10-3 kg m-I S-1