Introduction to Microcalorimetry and Biomolecular Energetics

As our knowledge of biomolecular structure becomes ever more detailed, it becomes increasingly important that we study the basic physical forces between and within macromolecules in sufficient detail, so that we might be able to understand and manipulate biological processes at the molecular level. Calorimetry is the only technique available for measuring these interactions directly, and microcalorimetric experiments have been performed on biological systems since at least the 1930s. It is only relatively recently, with improvements in calorimetric technology coupled with the advent of facile site-directed mutagenesis and genetic engineering methods, however, that these measurements have become relatively routine (1 –9 ). Commercial instruments are now available that are sufficiently sensitive, stable, user friendly, and cheap to allow microcalorimetry to become an almost routine analytical procedure in biochemical and biophysical research laboratories.