How Does Mass Spectrometry Identify Proteins?
Mass spectrometers identify proteins in a manner analogous to using fingerprints to identify a person. Each protein has a mass spectrum with unique characteristics. To minimize confusion, proteins must first be separated from protein mixtures; then they can be examined with a mass spectrometer. The most common form of protein identification with mass spectrometry uses a tandem mass spectrometer (abbreviated MS/MS). As explained below, identifying a protein with MS/MS is like identifying a person using fingerprints. Clarification: In the proteomics field, the term “Protein Mass Fingerprinting”, PMF, describes a simpler procedure using a simpler mass spectrometer. The broader analogy of MS/MS to fingerprinting is used here only to explain the concepts.
