The goal of this application is to enhance the mass spectrometry capabilities available to NIH investigators at Washington University School of Medicine and in so doing significantly strengthen the potential of those investigators to conduct outstanding biomedical research. This will be accomplished by the purchase of a modern Perseptive Biosystems MALDI-TOF mass spectrometer to complement the Finnigan LCQ ESI instrument already in operation. This instrument will enhance the capabilities of NIH supported investigators at Washington University by providing increased sensitivity, versatility of chemistry, and cost-effectiveness in mass spectrometry services. The instrument will be integrated into a Core Facility and be operated by the Washington University Protein and Nucleic Acid Chemistry Laboratories as a shared instrument for biomedical research. A major group of 6 NIH supported investigators has been identified as primary users whose research will be enhanced immediately by acquisition of the instrument. These investigators are funded by 5 different institutes of NIH and require the instrument for projects that include biochemical, biophysical, and structure-function studies in coagulation, the role of inositol phosphates in human disease, enzymatic mechanism of allostery, pili assembly in bacterial pathogenesis, RNA binding function, and gene expression in bone. In addition, the instrument will be utilized by an additional group of approximately 52 Acid Chemistry Laboratories. Finally, approximately 80 additional NIH funded investigators who use the Nucleic Acid Chemistry Laboratories have operated as a core service facility for over 15 years. Thus, all of the necessary requirements for scientific expertise, operation, maintenance, and cost-recovery are in place. In addition, the staff of the Protein and Nucleic Acid Chemistry Laboratories have over 5 years of experience in mass spectrometry analysis.