Biomolecules partition coefficient

The quality of separation depends on several factors, among them the partition coefficients of biomolecules between the phases, phase behavior, temperature, and the type and concentration of both salt and polymer. The partition coefficient of species X between the top and bottom phases is defined by Eq. (8.67). 

TABLE I Partition Coefficients of Some Biomolecules in Solvent Extraction... 

Aqueous two-phase systems are characterized by a high water content, which makes them compatible with the biological material. The distribution of biomolecules between the phases is determined mainly by their surface properties and the composition of the phase system, and is denoted by partition coefficient, Kpart, defined as the ratio of its concentration in the top and bottom phase, respectively. The partitioning is independent of the absolute concentration of the substance over a fairly wide range. Any substance prefers a phase where a maximum number of interactions are possible these could be related to electrical, hydrophilic, hydrophobic and conformational forces. Reports in the literature have shown that different characteristics of the system can be manipulated in order to achieve the... 

First, it is necessary to establish the phase diagram of the aqueous two-phase system formed by water and two water-soluble polymers. Second, a method must be established for calculating the distribution coefficient of a biomolecule that partitions between the two aqueous phases. A simple molecular-thermodynamic description is provided by the osmotic virial... 

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