Receptor molecules amino-acid recognition

The term chiral recognition refers to a process in which some chiral receptor or reagent interacts selectively with one of the enantiomers of a chiral molecule. Very high levels of chiral recognition are cormnon in biological processes. (—)-Nicotine, for example, is much more toxic than (-F)-nicotine, and (-F)-adrenaline is more active than (—)-adrenaline in constricting blood vessels. (—)-Thyroxine, an amino acid of the thyroid gland that speeds up metabolism, is one of the most widely used of all prescription... 

Rather than using the protein molecule as a whole, the imprinting of selected protein epitopes may present a more practical approach. Imprints of such patches may then act as receptors for these parts of the protein. It could be shown that an MIP imprinted with a tetrapeptide was able to recognize not only the template but also a protein bearing the same 3-amino acid terminus as the peptide template [129]. If this approach proves to be successful in other cases as well, MI-based recognition will no longer be limited to small molecules. The result will be even more antibody like biomimetic polymers. 

Calix[4]arene is a very popular building block for the design of molecules with well-defined mutual positions of substituents. The attachment of amidic residues to this molecule resulted in receptors 35 [65] and 36 [66]. Upon the H NMR titration of 35 by tetrabutylammonium salts of amino acids in acetone-d6y moderate chiral recognition was observed N-Ac-L-Ala K=4,900 M-1, AT-Ac-D-Ala K=5,700 M"1, AT-Ac-L-Phe iC=7,900 M-1, AT-Ac-D-Phe K= 10,500 M"1. The receptors 36a-c formed stable complexes with AT-tosyl-L-phenylalaninate in deuteriochloroform (36a K= 1,626 M"1, 36b 1C=4,836 M"1, 36c K=6y924 M-1). Unfortunately, the measurement using AT-tosyl-D-phenylalaninate has not been reported. 

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