This award supports the purchase of an Isothermal Titration Calorimeter (ITC) to be used for experimental thermodynamic analyses of biomolecular recognition and function. Calorimetric studies permit characterization of enzymatic reactions and, as well, study of non-covalent interactions between proteins and various other molecules, both large and small. The instrument will be placed in the University's core facility for protein studies where it will be available to faculty from throughout the institution. Initially, five investigators and thirty to fifty trainees in their laboratories are expected to be the major users. Planned studies that will use the instrument include the experimental identification of substrates of nitrilase-related enzymes; analysis of dual specificity tRNA synthetases; characterization of protein/DNA and protein/protein interactions important for avidity; measurement of the binding of small cyclic peptides and their cellular targets; and evaluation of the thermodynamics interaction of T-cell receptors and their natural signaling ligands. In addition to its use in research, the instrument will be used to support a curriculum change in the University's graduate biophysics course that will provide a new emphasis on calorimetric approaches to the study of molecular interactions.