Driving Forces for Adsorption of Globular Proteins

The adsorption behavior of globular proteins shares some features with that of flexible (charged) polymers, but in various ways it is different. 

Because of the relatively rigid structure of adsorbed globular protein molecules, the adsorption isotherms display well-defined plateau values. The adsorption pattern, the effects of pH (i.e., charge of the protein), and ionic strength are in agreement with those of a polyampholyte the adsorbed mass generally is at a maximum around the isoelectric point of the protein/surface complex, that is, at conditions where the charges on the protein and the surface just compensate each other. 

In the following section, the primary contributions determining protein adsorption affinity reflected by the Gibbs energy of adsorption are considered in more 

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