Biomacromolecules, separation, general

For the HPLC separation of low molecular weight organic compounds and various biomacromolecules, the near-equilibrium criterion has generally been assumed for the binding and desorption behaviour. Changes in thermodynamic parameters due to polypeptide- or protein-ligate interaction can thus be depicted in terms of the Gibbs-Helmholtz relationship, namely,... 

Gel filtration/permeation chromatography (also known as molecular exclusion chromatography) is a form of partition chromatography in which the solute molecules are partitioned between solvent and a stationary phase of defined porosity without an attractive interaction between the two phases. Gel filtration generally refers to aqueous systems while gel permeation is used in nonaqueous systems. The technique is normally used for the separation of biomacromolecules on the basis of size. Solutes are eluted in the order of decreasing molecular size. Gel filtration chromatography is not used as the first step in... 

Ion-exchange chromatography is generally used in an early stage of biomacro-moleeular purification. It is used to separate neutral biomacromolecules (e.g. neutral polysaccharides) from charged biomaCTomolecules such as nucleic acids versus proteins. 

Of equal importance, the use of RPC and HIC techniques provides a very powerful avenue to explore the molecular basis of the hydrophobic effect per se that these biomacromolecules exhibit. Since the time of the initial attempts, commencing over 50 years ago, to exploit the hydrophobic effect as part of robust separation procedures, RPC and HIC have thus come to assume a dominant position for the isolation and analysis of many proteins and now represent the techniques par excellence for the purification and analysis of polypeptides prepared by solid- or solution-phase synthetic procedures. Equally, these techniques provide an opportunity to explore the role of the hydrophobic effect in the stabilization and folding of proteins and polypeptides, the molecular forces that are involved in these processes, the thermodynamics of their interaction with relatively well-defined nonpolar surfaces, and the biophysics of peptide or protein nonpolar interactions in general. 

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