1. Macromolecular hydration compared with preferential hydration
The difference between macromolecular hydration and preferential hydration drives the diffusion of macromolecules from high to low concentration of an osmolyte.

2. Quaternary diffusion in enzyme-polymer-salt-water systems
Fick’s law for the enzyme(1)-polymer(2)-salt(3)-water system
Solute
Concentration
Gradients
Solute
Fluxes
Diffusion Coefficients

3. Enzyme diffusion coefficient D11
Lysozyme main-diffusion coefficient, D11 , as a function of PEG2000 concentration, C2, and NaCl concentration, C3 , at pH 4.5 and 25 °C. Quaternary data points ( ) are shown together with previously reported ternary data for the lysozyme-PEG2000-water ( ) and lysozyme-NaCl-water ( ) systems.

4. Enzyme aggregation at the liquid-liquid interface
Figure 6. (A) Liquid-liquid interface between a phase rich in poly(ethylene glycol) (top phase) and a phase rich in ammonium sulfate (bottom phase). Enzyme at low concentration is initially in the bottom phase. The interface is depleted of both cosolvents. (B) Enzyme molecules diffuses towards the interface and remains there due to the local concentration gradients of the two cosolvents. (C) Formation of laccase film at the liquid-liquid interface. It is important to remark that laccase aggregation is not observed in the two phases taken separately. Laccase films are catalytically active.