402 Part III: Muscle Foods
Figure 18.1.An overview over the ‘classic approach’ in proteomics. First, a protein extract (crude or fractionated)
from the tissue of choice is subjected to two-dimensional polyacrylamide gel electrophoresis. Once a protein of inter-
est has been identified, it is excised from the gel and subjected to digestion by trypsin (or other suitable protease).
The resulting peptides are analyzed by mass spectrometry, yielding a peptide mass fingerprint. In many cases this is
sufficient for identification purposes, but if needed, peptides can be dissociated into smaller fragments, and small
partial sequences can be obtained by tandem mass spectrometry. See text for further details.