Hydrophobicity of biosurfaces — Origin, quantitative determination and interaction energies

It is shown that the “hydrophobic” attraction energy between two apolar moieties (as well as between one polar and one apolar moiety) immersed in water is the sole consequence of the hydrogen-bonding energy of cohesion of the water molecules surrounding these moieties. It is also shown that “hydrophobic” surfaces do not repel, but on the contrary attract water. The theory is given of hydrophobic interactions at a macroscopic level, as well as various methods for their quantitative measurement. The properties of hydrophobic, partly hydrophobic and hydrophilic compounds and surfaces are described, including those of amino acids, proteins (incorporating protein solubility), proteins at the air-water interface, carbohydrates, phospholipids, phospholipid layers, and nucleic acids. Finally, some effects and applications of hydrophobic interactions are discussed, including protein adsorption, protein precipitation, cell adhesion, cell fusion, and liquid chromatography approaches such as reversed-phase and hydrophobic interaction chromatography. Finally, the influence of hydrophobic forces is treated in antigen-antibody and other ligand-receptor interactions.