- Peptides & proteins with blocked N-terminal amino groups (e.g. acetylated, formylated) will not sequence by Edman degradation.
- High molecular weight proteins (over 75 kDa) may prove difficult to be analyzed. In our experience, the foremost reason is sample quantity and / or purity. However, reasonably pure protein bands and comfortable amounts will allow for unambiguous sequence calls. Please contact us before sending your sample.
- Unmodified Cys and glycosylated residues will give a blank cycle (i.e. residue is cleaved off the peptide chain but is not detected by HPLC at 270 nm).
- Sample quality is critical. Any impurity that interfers with Edman’s chemistry (mainly amine-containing chemicals) will lead to poor results.