Solubilization acidic side chain

Integral proteins are dissolved into the lipid bilayer of the membrane through interactions of the hydrophobic amino acid side chains and fatty acyl groups of phospholipids. In order to remove integral membrane proteins, the membrane must be disrupted by addition of detergents or other chaotropic reagents to solubilize the protein and to prevent aggregation and precipitation of the hydrophobic proteins upon their removal from the membrane. 

Some acids associate strongly with the reverse micellar interface, and those do not control the solubilization. This depends on the strength of the interactions with the interface and the hydrophobic effect on the acid side chain (Albery et al., 1987 Leodidis and Hatton, 1989 Luisi et al., 1988 Steinmann et al., 1986). There are some possible residence sites for hydrophilic solutes in reverse micelles. 

The amphiphilic molecules constituting the micelles can be surfactants, like sodium dodecyl sulfate (SDS) for the solubilization of artemisinin and curcumin or for the delivery of polyphe-nolic fractions from Hamamelis virginianaP The micelles can also be formed of synthetic block copolymers. For example, copolymers of caprolactone 2-(methacryloyloxy)ethyl ester units with poly(meth)acrylic acid side chains have been self-assembled in micelles of quercetin associated with indomethacin for the treatment of inflammatory diseases (Figure 36.10). Resveratrol has been loaded into PCL-PEG micelles for its protective effect against oxidative stress. An aqueous formulation of luteolin has been developed with the same PCL-PEG micelles, with potential anticancer effect. ... 

Their results indicated that PEO-b-PHSA micelles with a high level of stearic acid side chain substitution, at 50% and 70%, can solubilize AmB effectively, reduce its hemolytic activity yet retain its potent antifungal effects. 

Substitution Reactions on Side Chains. Because the benzyl carbon is the most reactive site on the propanoid side chain, many substitution reactions occur at this position. Typically, substitution reactions occur by attack of a nucleophilic reagent on a benzyl carbon present in the form of a carbonium ion or a methine group in a quinonemethide stmeture. In a reversal of the ether cleavage reactions described, benzyl alcohols and ethers may be transformed to alkyl or aryl ethers by acid-catalyzed etherifications or transetherifications with alcohol or phenol. The conversion of a benzyl alcohol or ether to a sulfonic acid group is among the most important side chain modification reactions because it is essential to the solubilization of lignin in the sulfite pulping process (17). 

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