The conformational isomers of a biogenic substance may present isomer-specific bioactivities when the isomers have different binding forces towards a particular receptor because of differences in geometrical relations so as to form the supramolecular complexes individually with distinct thermodynamic stabilities. The correct determination of the individual stabilities is the first step to study the isomer-specific effects. It can be performed by NMR titration, the application of which has demonstrated the isomer-specific supramolecular complexation of D-glucosamine. The NMR studies extended to a variety of biogenic isomers would establish the isomer-specific molecular interaction and the consequent isomer effects on the bioactivities. This review article outlines the principles and experiments of the NMR-titrimetric method, together with a convenient data-analysis process using Excel® spreadsheets, to facilitate its use in biochemical research.
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