Tryptic peptide tagging for visualization using trypsin

CHED 262

Tim Tucker, bholloway@schreiner.edu and Robert Holloway, bholloway@schreiner.edu. Department of Sciences and Mathematics, Schreiner University, 2100 Memorial, Kerrville, TX 78028
The peak capacity of a multidimensional separation method is sufficient to analyze extremely complex mixtures. The mixture of peptides obtained from enzyme catalyzed lysis of a protein can be used to count the fragment peptides. This is now done using mass spectrometric detection. It is desirable to use techniques like UV-Vis which are cheaper. The UV absorbance of a single amino acid is much less than the other cleavage products. Labeling of peptides is possible but individual residues contain reactive side chains which react with the labeler. We have pursued a selective tagging method, the use of trypsin both as a cleavage catalyst and a labeling catalyst. To this end we have attempted to form a peptide bond using trypsin which has been done in other contexts We report our attempts involving lysine as a model fragment and the beta-napthylamide of gly-phe as a UV absorptive label.