Faculty in the Departments of Biochemistry, Chemistry and Biology at Brandeis University are requesting funding for a MALDI-TOF (Matrix- Assisted Laser Desorption Ionization Time-Of-Flight) mass spectrometer. This instrument will be placed in the Core Biomolecules Synthesis and Analysis Facility. It will be freely accessible to all NIH-supported researchers in the School of Science at Brandeis, as well as others on a time-available basis. Currently there is no mass spectrometer at all at Brandeis; at the present time the 13 investigators in the major user group must seek off-campus collaborations to carry out any mass spec analysis of any variety. Therefore acquisition of a state-of-the-art MALDI-TOF mass spectrometer will significantly expand the life science research capabilities at this institution. Immediate uses proposed by the major user group include routine analysis of the products from organic and bioorganic synthesis (e.g. synthesis of natural products, modified nucleic acids, functionalized proteins, enzyme inhibitors and ion channel blockers), mapping sites of post-translational modifications in proteins, monitoring changes in phosphorylation states of proteins, rapid sequencing of new proteins and peptides, monitoring isotope labeling of proteins for NMR analysis, monitoring metal ion replacement in metalloproteins, mapping sites of protein modification by active site-directed inactivators of enzymes and kinetic analysis of peptide bond cleavage by proteases. Institutional commitment for acquisition and maintenance of a state-of- the-art MALDI-TOF is very strong. In particular, the University will provide for the salary of the Principle Operator, as well as guarantee funds for maintenance of the instrument into the foreseeable future.