Synthetic support structures

The Nishino studies represented the first attempt to incorporate flavin functionality into a synthetic and structured polypeptide motif. As with the Kaiser systems, it is possible that the observed rate enhancements are a result of the association of the hydrophobic substrates with the hydrophobic core of the bundles. The use of SDS to increase accessibility to the flavin would seem to support this. However, it is also possible that the placement of the flavin into the hydrophobic core has decreased its reduction potential and that the SDS interacts with the bundle to create a slightly more hydrophilic environment for the flavin while preserving some of the hydrophobicity for substrate binding. 

A similar approach utilizing cellulose paper (27,28) (originally developed for DNA synthesis [29J), was later modified by using a printer to label individual pieces of synthetic support (30). Cotton, as the most pure form of cellulose, was found to be a convenient support for parallel synthesis as well (31-34), and was used for the synthesis of combinatorial libraries with guaranteed uniform representation of each structure (35). 

Flnorous synthesis An approach to solution-phase synthesis that uses highly niiorinated compounds as soluble. supports for combinatorial chemistry. The addition of water nr organic solvents causes a phase separation of the fluorinatcd support for subsequent cleavage of the synthetic target structure. 

Magnesium oxide, y-aluminum oxide, synthetic rutile, thorium dioxide, silica gels, barium sulfate, activated carbons, metallic network supporting structures, various silicates (especially of Mg, Al), etc. 

Polymer-based, synthetic ion-exchangers known as resins are available commercially in gel type or truly porous forms. Gel-type resins are not porous in the usual sense of the word, since their structure depends upon swelhng in the solvent in which they are immersed. Removal of the solvent usually results in a collapse of the three-dimensional structure, and no significant surface area or pore diameter can be defined by the ordinaiy techniques available for truly porous materials. In their swollen state, gel-type resins approximate a true molecular-scale solution. Thus, we can identify an internal porosity p only in terms of the equilibrium uptake of water or other liquid. When crosslinked polymers are used as the support matrix, the internal porosity so defined varies in inverse proportion to the degree of crosslinkiug, with swelhng and therefore porosity typically being more... 

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