ABSTRACT
This chapter argues that optical rotatory dispersion (ORD) and circular dichroism (CD), but especially the latter, are useful techniques for the investigation of the conformation of biological macromolecules in solution, of the stability of such a conformation in the presence of perturbants such as cations, salts, denaturing agents, or heat. It describes the contributions of such chromophores to CD spectra, and, especially, the utilization of difference CD spectra in determining the alteration in the environments of specific chromophores. The literature pertaining to studies of the thermal denaturation of proteins by measurement of the peptide CD bands has been extensively reviewed. The study of intrinsic contributions by sugar residues to the CD spectrum of polysaccharides is in its early stages, since the region in which such contributions are made lies in the heretofore inaccessible vacuum ultraviolet region of the spectrum. The ORD/CD signal will reflect the individual or the sum of the contributions of the transitions of these chromophores.
