• Overview
• Affinity Isolation
• Affinity Purification
• Data Mining »
  • Vizualisations
  • Bioinformatics
  • Bead Proteomes & the PFL

Samples analysed by mass spectrometry can vary in complexity. Samples that are derived from whole cells, tissues or organisms constitute highly complex mixtures of proteins, in which all expressed proteins could theoretically be identified (up to 20,000 proteins). Alternatively, subsets of cellular proteins can be specifically enriched by fractionation/isolation, before being analysed by MS.

Different types of fractionation are commonly used in cell biology:

• cellular fractionation (isolation of cellular organelles, such as the cytoplasm, nucleoplasm, nucleolus, etc).
• affinity-purification of protein complexes, by immunoprecipitating the protein of interest (bait) and associated proteins (interaction partners).
• isolation of proteins that show a specific post-translational modification (phosphorylation, sumoylation, ubiquitinylation, etc).