The proteome represents the total set of proteins produced by an organism or a system at a particular time or state, with proteomics being the study of the proteome. The proteome is a dynamic system wherein proteins are interconnected and serve to facilitate cellular processes in a concurrent and coordinated manner. Over the years, various biochemical and biophysical methods have been developed to elucidate the identities, structures and functions of proteins in order to understand their roles in complex biological systems. The success of proteomic approaches hinges on efficient protein extraction and sample preparation; however, these preliminary steps are often considered a bottleneck in proteomic workflows. Every biological sample is unique and complex, and sample processing needs to be tailored to the nature of the protein sample due to its vulnerability towards post-collection degradation and the complexity of its non-protein constituents. Sample pretreatment steps often employ buffers, solvents, salts and detergents that are not always compatible with the downstream analytical tools. This chapter will provide an overview of sample pretreatment techniques commonly used in conjunction with proteomics tools and discuss protein analysis methods. Such methods include the use of antibody-based techniques, separation sciences (e.g. chromatography, SDS-PAGE), detection methods (e.g. mass spectrometry) and structural techniques (e.g. NMR and X-ray crystallography).
Keywords: ELISA; Immunohistochemistry; Mass spectrometry; NMR; Proteomics; Sample preparation; Western blot; X-ray crystallography.