The Biacore T100 is a state-of-the-art surface plasmon resonance instrument that combines high sensitivity with automated high throughput, making it an ideal instrument for the study of biomolecular interactions. No comparable instrument currently exists on campus. The group of investigators is composed of 5 major users, all of whom are NIH funded. All of the users are performing quantitative studies of biomolecular interactions, investigating a broad range of systems, including protein-protein, protein-small molecule.protein-nucleic acid and protein-carbohydrate interactions. Knowledge of the thermodynamic and kinetic parameters of molecular interactions is a critical step in characterizing the regulation and catalysis of numerous biological pathways. The Biacore T100 enables a broad spectrum of experiments including: thermodynamics, solution-affinity, concentration analysis, and kinetics. This instrument is the successor of the Biacore 3000 and allows for rapid screening of multiple ligands to multiple interacting partners under a variety of conditions (concentration, pH, ionic strength, temperature, etc.), and the high sensitivity requires very little sample in cases when amounts of the biomolecules are limiting. This instrument will complement UMass Medical School's institutional commitment for investigating biological macromolecules, which already includes mass spectrometry, microscopy, x-ray crystallography, calorimetry and NMR. The proposed instrument purchase will fill acute research needs for NIH-funded investigators at UMass Medical School.