Nonspecific hydrophobic attractions

Nonspecific hydrophobic attractions are Important to the dissociative-associative reactions which Inltate the gelation process. These attractions could also be Involved In layering or thickening of the gel network strands upon cooling which results In Improved strength and stability. This thickening of gel network strands also results In Increased opacity (8). 

Some authors have suggested the use of fluorene polymers for this kind of chromatography. Fluorinated polymers have attracted attention due to their unique adsorption properties. Polytetrafluoroethylene (PTFE) is antiadhesive, thus adsorption of hydrophobic as well as hydrophilic molecules is low. Such adsorbents possess extremely low adsorption activity and nonspecific sorption towards many compounds [109 111]. Fluorene polymers as sorbents were first suggested by Hjerten [112] in 1978 and were tested by desalting and concentration of tRN A [113]. Recently Williams et al. [114] presented a new fluorocarbon sorbent (Poly F Column, Du Pont, USA) for reversed-phase HPLC of peptides and proteins. The sorbent has 20 pm in diameter particles (pore size 30 nm, specific surface area 5 m2/g) and withstands pressure of eluent up to 135 bar. There is no limitation of pH range, however, low specific area and capacity (1.1 mg tRNA/g) and relatively low limits of working pressure do not allow the use of this sorbent for preparative chromatography. 

It appears that the proteins locating on the in vivo PHA granule surface could be potential affinity tags for protein purification. Among the nonspecific PHA granule-binding protein phasin as a hydrophobic affinity tag appears to be the most attractive because of its richness compared with others. 

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