Peptide mass fingerprinting

A peptide mass fingerprint (PMF ) ( Sheet protein fingerprinting ) is an analytical technique for identification of proteins of Biochemistry by SDS-PAGE, protease digestion and mass spectrometry. The peptide mass fingerprint was developed by several groups independently in 1993.

Principle

In this method, an as yet unknown first protein, usually digested by the protease trypsin by a in-gel digestion, into smaller peptides whose absolute compositions are very accurately with a mass spectrometer such as MALDI -TOF or ESI-TOF measured can. These measured masses are then compared either with those of a database such as Mascot for known protein sequences or even with those of a genome database. This is made possible by the use of computer programs which translate the known genomes of organisms into proteins, then these proteins theoretically intersect ( in silico ) into peptides, and then calculate the absolute masses of the peptides. Finally, the measured masses of the peptides of the unknown protein are compared with the theoretical peptide masses and the results statistically analyzed to find the best match.

The advantage of this method is that only the masses of the peptides need to be known. A time-consuming protein sequencing of the peptides is then not required. The disadvantage is that the target protein sequence must be found in a database, such as Mascot. In addition, most of algorithms Peptimassenfingerprinte assume that the peptides are derived from only a single protein. When a protein mixture is unavoidable, the analysis is complicated and may lead to incorrect results.

Important for the identification of proteins by peptide mass fingerprinting, therefore, the previous protein purification. Mixtures of more than two to three proteins require additional use of MS / MS -based techniques for the identification of proteins in order to achieve adequate specificity of the identification. Therefore, appropriate samples for peptide mass finger Printe from 2D gels truncated protein spots or individual SDS -PAGE bands after in-gel digestion.

Alternatives to peptide mass fingerprint are eg Edman degradation or molecular display followed by DNA sequencing.

Swell

• Medical laboratory investigation procedure
• Biochemical method
• Mass spectrometry
• Protein