[Transport of low molecular weight substances in protein crystals and films]

Diffusion of synthetic dyes in lysozyme crystals and bovine serum albumin (BSA) amorphous films is shown to depend on the size of diffusate molecule far more strongly than in solutions. The diffusion coefficient increases from 10(-8) to 10(-13) cm2 sec-1 on about 1.5 divided by 2--fold increase in diffusate dimensions, the diffusion being completely arrested on reaching the limiting dimensions of about 14 A and 12 A for BSA films and lysozyme crystals, respectively. The diffusion in lysozyme crystals is anisotropic, with a diffusion maximum directed along their screw axes. The diffusion coefficient dependence on the charge of diffusate and its binding to proteins is discussed.