Sample Preparation
Protein samples can be derived from SDS-PAGE and are then subject to some chemical modifications. Disulfide bridges in proteins are reduced and cysteine amino acids are carboxymethylated chemically or acrylamidated during the gel electrophoresis.
Then the proteins are cut into several fragments using proteolytic enzymes such as trypsin, chymotrypsin or Glu-C. A typical sample:protease ratio is 50:1. The proteolysis is typically carried out overnight and the resulting peptides are extracted with acetonitrile and dried under vacuum. The peptides are then dissolved in a small amount of distilled water or further concentrated and purified using ZipTip Pipette tips and are ready for mass spectrometric analysis.
Read more about this topic: Peptide Mass Fingerprinting
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