TARGET PRACTICE: Free computational tools available on the Web can simplify a few of the steps involved in developing an SRM/MRM assay. Once developed, an assay will need to be further refined and validated by the researcher.
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Mass spectrometers can quickly spit out spectra of an organism’s complete complement of proteins, known as the proteome. Shotgun experiments, also known as data-dependent analyses, aim to ID as many sample proteins as possible. “This is a great method to establish a protein inventory of a cell or tissue,” says Ruedi Aebersold of the Swiss Federal Institute of Technology in Zurich. “But it is less well suited to compare precisely the abundance and presence of specific proteins across many samples.”
That’s where a targeted mass spectrometry technique known as selected reaction monitoring (SRM) can come in handy. It’s a tried-and-true method that has been around for decades. “With the SRM approach, you program the machine in advance to look for a specific peptide that you ...
