Final answer:
Tandem mass spectrometry can determine peptide sequences, detect post-translational modifications, and identify proteins in a sample by analyzing the mass and sequence of peptide fragments and comparing them against protein databases.
Step-by-step explanation:
Tandem mass spectrometry (MS/MS) is an advanced method for protein analysis that can determine multiple parameters of a protein sample. This powerful technique can provide detailed information on the peptide sequence of proteins, thereby enabling the identification of the proteins present in a sample. It is also capable of detecting and analyzing post-translational modifications (PTMs), which are chemical modifications that occur after a protein has been synthesized. These modifications can significantly affect the protein's function and are therefore important to identify.
During the process of tandem mass spectrometry, proteins are typically digested into peptides, which are then separated and analyzed in the mass spectrometer. The resulting spectra are compared against databases to identify the proteins (Protein identification) and their post-translational modifications. Moreover, advances in mass spectrometry and computational tools have greatly enhanced the accuracy and speed of protein identification and characterization. Combining tandem mass spectrometry with liquid chromatography (LC/MS/MS) further improves the resolution and sensitivity of the analysis, allowing for the detection of even low-abundance proteins and subtle PTMs.