| Description | This approach leads to protein identification by matching peptide masses, as measured by mass spectrometry, to the ones calculated from in silico fragmentation of a protein sequence database. A peptide mixture from a tryptic digest is analysed by MALDI-MS (Matrix-assisted laser desorption ionization mass spectrometry). The list of peptide masses obtained by MALDI MS is automatically compared to the calculated masses of the predicted peptide fragments for each entry in the database. High mass accuracy is very important in order to obtain a statistically significant and unambiguous match This method is best applied to completely sequenced genomes and well characterised proteomes. However, depending on the data quality, proteins that are highly homologous to already characterised proteins (greater than 80 to 90% sequence identity) can also be identified. The retrieved sequence are evaluated by mass accuracy of the peptides, matching of additional peptide masses in the MALDI spectrum after accounting for common modifications such as oxidation, acrylamidation of cysteine and missed cleavages and the use of secondary information (apparent isoelectric point and molecular weight). If any ambiguity about the identification by MALDI-MS still exists, the results must verified by an other identification method. Peptide mass fingerprint is generally carried out with a MALDI-TOF (Matrix-assisted laser desorption ionization time-of-flight ) instrument but can also be achieved ESI-TOF (Electrospray Ionisation time-of-flight) or LC-MS (Liquid Chromatography-Mass Spectrometry) mass spectrometer. | Namespace | PSI-MI |
| Obsolete | false |
Ontology Term --> All ancestors
Ontology Term --> All descendants
Ontology Term --> Direct children
Ontology Term --> Direct parents
