Question

Why is tandem mass spectrometry more useful in analysis of peptides and proteins?

Answer 1

Tandem mass spectrometry or MS/MS is used to measure fragmentation spectra and identify proteins at high speed and accuracy. The principle of MS/MS is that ions from a sample is formed and separated by mass-to-charge ratio in the first stage of mass spectrometry (MS1). Then a particular m/z value of interest is selected from the mass spectrum and fragment ions are created by collision-induced dissociation. The fragment ions so generated are separated and recorded by the second mass analyzer (MS2).

It is important to note that collision-induced dissociation that is used to generate fragment ions from a specific peptide ion primarily gives rise to cleavage products that break along peptide bonds only. It is due to this kind of fragmentation of peptide ions, which makes it possible to use the observed fragment masses to match with a database of predicted masses for various different peptide sequences and protein molecules. This is why tandem mass spectrometry is more useful in analysis of peptides and proteins.

Thanks!