Mass spectrometry of proteins

Over the past two decades, mass spectrometry has revolutionized protein analysis, developing as a mainstream neuroproteomic technology well suited to studying protein structure and function. This article presents an overview of mass spectrometric instrumentation and approaches used to detect, sequence, and identify proteins in biological samples without the use of specific molecular probes and labels, often directly in brain tissue and cells. Strategies for mass spectrometric determination of the absolute and relative amounts of selected proteins in a sample are described. Application of mass spectrometry to the analysis of structural variability, posttranslational modifications, protein interactions, and biomarker discovery are highlighted.