mass detection of residue modification

^ http://purl.obolibrary.org/obo/MI_0068

Mass spectrometry can be used to characterise chemical modifications within peptides. One approach consists in the observation of a mass difference when a sample is treated with an enzyme that can specifically remove a peptide modification, for instance a phosphatase. The mass difference corresponds to the mass of the chemical group covalently linked to a residue. Such experiments carried out with a MALDI-TOF (Matrix-assisted laser desorption ionization time-of-flight ) do not allow the mapping of the modification site within the sequence, whereas any tandem mass spectrometer (LC MS/MS Liquid Chromatography Tandem Mass Spectrometry, nanoESI MS/MS nanoElectrospray Ionisation tandem mass spectrometry, FTMS Fourier Transform mass spectrometry) provide such information. A second approach consists of the direct mass measurement of the ionized chemical group dissociated from the residue within a tandem mass spectrometer. Both approaches need a prior enrichment of the modified peptide population in the samples with IMAC (Immobilized Metal Affinity Chromatography)or specific anti-modification antibodies. [ http://www.ncbi.nlm.nih.gov/pubmed/11395414 PMID for application instance:11875433 ]

Synonyms: modified residue ms

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