DESCRIPTION (provided by applicant): In the last decade the NIH has invested billions of dollars to place cutting-edge MS instrumentation in laboratories across the US. Several other Federal entities, along with private and academic institutions, have likewise contributed, such that a research institute without at least one state-of-the-art MS system is now the exception to the rule. For all this investment, biomedical researchers lacking MS expertise can now submit samples, mostly to core facilities but also to expert collaborators, for protein analysis. This analysis most often results in a list of proteins present in a sample. More seasoned facilities wil have in-house expertise in PTM analysis and may, for example, offer phosphorylation site analysis on targeted proteins or complex mixtures. Considering where the field of proteomics was just fifteen years ago-low throughput peptide mass mapping from gel bands-broad access to today's protein analysis is remarkable. Doubtless this success stems from the sizeable investment of NIH and other funding agencies in fundamental technology development. That said, global protein quantification methodologies, either relative or absolute, are not routine even for most expert laboratories. The result is highly rationed access to arguably the most valuable and telling type of proteomic data. Understanding the networks that regulate complex organisms and their diseases will require wide and pervasive access to these critical comprehensive technologies. The NCQBCS will catalyze and expedite this transformation in quantitative biology.