Recognition of lysine residues on protein surfaces using calixarenes and its application

A macrocyclic calix[6]arene carboxylic acid derivative is found to extract lysine-rich protein cytochrome c from aqueous media into organic media through the complexation between the calixarene molecules and lysine residues on the surface of the protein. This article summarizes both the mechanism of protein extraction by the calixarene as well as the potential applications of the extraction process. The extraction process can be used for the purification of proteins through selective extraction and back-extraction under optimized conditions. On the other hand, the extracted protein exhibits enzymatic activity in organic media. The formation of a supramolecular complex by recognizing the residues on a protein surface can be construed as a novel recognition and/or modification method for biomacromolecules.