Interest is growing in the application of Fourier-transform infrared (FTIR) spectroscopy to the study of biomolecules in an aqueous environment. The increasing popularity of the technique is due to its ease of application to determine the secondary structure of peptides, proteins and also membrane proteins within their native lipid bilayer matrix. The ability to probe structural changes at a molecular level as a function of light, heat, pH or other external factors using difference spectroscopy is making a detailed understanding of the mechanism of action of different proteins possible. The use of isotopically labelled molecules helps in both the assignment of spectra and the attainment of greater specificity, and provides a new approach for the study of protein-protein interactions.
