Protein mixtures in aqueous solution are commonly separated by molecular sieve chromatography. An important aspect of this separation process is the diffusion of the protein into the porous matrix of the chromatography support used to affect the separation. Estimate the effective diffusion coefficient of the enzyme urease in a single 100-nm-diameter cylindrical pore. The molecular diffusion coefficient of urease in water at infinite dilution is 3.46 10^–7 cm²/s at 298 K, and the diameter of the molecule is 12.38 nm.