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.