C.I. Rationale and Objectives The application of mass spectrometry approaches to many facets of this Program Project is a unique aspect of this research program. The purpose of this Core is to provide mass spectrometry support for investigators within the Program Project. The Core will serve as a centralized area of expertise in analytical, biophysical, and structural techniques that rely upon mass spectrometry. The Core will also function as an educational facility for training members of the Program Project laboratories. Centralizing these aspects of the work and training will greatly enhance efficiency and productivity of the scientists participating in each project.