Nonspecific hydrophobic effect

Physical properties of the protein structure should be considered in designing strategies to achieve stable formulations because they can often yield clues about which solution environment would be appropriate for stabilization. For example, the insulin molecule is known to self-associate via a nonspecific hydrophobic mechanism66 Stabilizers tested include phenol derivatives, nonionic and ionic surfactants, polypropylene glycol, glycerol, and carbohydrates. The choice of using stabilizers that are amphiphilic in nature to minimize interactions where protein hydrophobic surfaces instigate the instability is founded upon the hydro-phobic effect.19 It has already been mentioned that hydrophobic surfaces prefer... 

Figure 8 Monitoring effect of nonspecific, hydrophobic interactions on strong CEC columns Columns A, PolySulfoethyl Aspartamide (200 x 4.6mm ID, 5pm particle size, 300 A pore size PolyLC, Columbia, MD) B, Mono S HR 5/5 (50 X 5 mm ID, 10 pm Pharmacia, Don/al, Canada). Mobile phase linear AB gradient, where buffer A is 5 mM aqueous KH2PO4, pH 6.5, and buffer B is buffer A plus 1 M NaCl, both buffers containing 5% (top) or 10% (bottom) acetonitrile (v/v) gradient rate, 20 mM NaCI/min, following 5-min isocratic elution with buffer A flow rate, 1 mL/min temperature, 26 C. The sequences of peptide standards Cl, C2, C3, and C4 (+1, +2, +3, and +4 net charge, respectively) are shown in Table 1.

In addition to protein detection using specific antibody/antigen and aptamer/protein interactions, array detection was demonstrated based on nonspecific interactions between the CPE/dye-labeled ssDNA complexes and proteins [103]. The design concept is motivated by the fact that external agents can effectively perturb the electron coupling of optical units within the complex of CPE/ssDNA-C and in turn vary the FRET-induced fluorescence of both CPE (donor) and C (acceptor). Owing to discrepancies in local hydrophobic and charged domains of different... 

We suggest therefore that for a minimum to occur in the standard free energy of transfer function of a solute in aqueous binaries we need a structural (nonspecific) effect (related here to the hydrophobic character of the cation) in the water-rich region and superposed to it, classical solute-solvent interactions with predominant water-solute interactions. 

---