Application of computerized infrared and Raman spectroscopy to conformation studies of casein and other food proteins

Summary The ability of modern biotechnology to produce new or modified proteins has outpaced current understanding of the relationship between protein structure and protein function. Resolution-enhanced infrared spectroscopy and Raman spectroscopy are excellent non-destructive techniques for investigating the secondary structure of proteins under a wide variety of conditions. The techniques yield rapid, reliable estimates of the proportion of helical structure, -strands, and turns of proteins in solution, as gels, or as solids. These methodologies can also detect subtle variations in protein conformation that frequently occur upon change of the biomolecular environment. In particular, it is possible to study structural changes which arise from alterations in pH, ionic strength, nature of solvent, and from interactions with other molecules or ions, such as another protein or Ca²⁺ ions. The first part of this paper will briefly review various important aspects of the techniques. The subsequent part describes application to structural problems of casein and other food proteins.