Proteinaceous receptor

Molecular imprinting technologies have found a niche in separation science. MIPs offer a good alternative to proteinaceous receptors and have been successfully used in affinity-based separations. Furthermore, the polymeric nature of the MIPs bears attractive features for applications that could not be achieved by antibodies or enzymes gas chromatography, solid-phase microextraction, etc. As further fundamental research and apphcation efforts are invested in MIP technologies, it is expected that MIPs will soon be commercialized. MIP-SPE is expected to the first commercial application area. 

Since sweet natural products often co-occur in complex mixtures with bitter- and/or neutral-tasting analogs, it is germane to mention briefly some of the presently held views on the mechanism of sweet taste reception. Although sweet taste chemoreception is thought to be mediated by proteinaceous receptor sites located on the microvillus membrane of taste cells of the... 

The nature of the receptor-sites responsible for odorotis interactions has not yet been elucidated. Some experiments suggest the presence of specific proteinaceous receptors, whereas... 

The interactions of D-glucopyranose, D-fructopyranose, and sucrose with a proteinaceous receptor have been examined by use of CPK models to validate the steieomolecular inteipretation of sweet taste proposed for these sugars. In continuation of earlier studies (see Vol. 24, Chapter 2, ref. 7) the kinetic effects of 17 free sugars on the hydrolysis of l-benzoyl-3-phenyl-l,2,4-triazole have been measured. Analysis of the results in terms of hydration and stereochemical features led to the conclusion that the relative positions of 2-OH and 4-OH in the sugars are critical. ... 

Insertion of modified receptors into liposomal bilayers. Bilayers of liposomes consist of phospholipid assemblies that hold individual Upid molecules by weak van der Waals forces. Ligands or receptors with surface-active groups can be inserted into liposomal bilayers (Fig. 5c). Proteinaceous receptors are usually nonamphiphilic, and hence they can be modified with alkyl chains or lipids that can be positioned along the hydrophobic part of bilayers. Then the relatively hydrophilic receptor part is exposed to the liposomal surface and can interact with ligands of cell surfaces [37,38]. 

Modified or intermediate liposomes can be obtained by direct mixing of lipids and receptor-modified lipids, by direct reaction of intermediate-modified liposomes with receptor or ligands, or by insertion of modified receptors into the liposomal bilayer. Proteinaceous receptors may be modified with alkyl chains or lipids positioned along the hydrophobic part of the bilayers. Covalent coupling methods have been attempted to bind proteins to functional groups on a liposome surface or to attach a hydrophobic residue covalently to the proteins and allow it to intercalate noncovalently into the bilayer dining or after the formation of the liposome. 

---