A membrane with a hydraulic conductance of 0.01 mL cm² psi¹ min¹ is used for the filtration of a protein solution at a concentration of 200 g L^-1. The hydrodynamic pressure drop applied across the membrane is equal to 15 psi, and the filtrate flux rate at 20 C is 0.140 mL cm^-2 min^-1. Estimate the molecular weight of the protein.