Can a protein be identified by mass spec if it is detectable by western blot?
Protein detection with antibodies and ECL reagents require only a few hundred molecules whereas peptide identification by mass spectrometry works well in the femtomole range which makes it 6 to 8 orders of magnitude less sensitive than a western blot. Furthermore, there’s little need to carry out extensive purifications and enrichments steps to detect specific proteins by western blots in a complex protein mixture. When carrying out mass spec analysis of a complex sample, the presence of more abundant proteins components will likely mask the detection of peptides from the proteins of interest. Fortunately, antibodies can be used to enrichment for proteins of interest and/or its interacting partners by performing immunoprecipitations. It is highly recommended to use immobilized antibodies so as to reduce the interference from antibody heavy and light chains during subsequent 1D gel or mass spec analysis.
Related Questions
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