Edman Degradation/Asp

Paul Tressel (pault@allelix.com)
Tue, 30 Mar 1999 10:42:38 -0500

I've been sequencing a peptide with several Asp residues, one of which
readily forms an aspartimide and which can be readily induced to form a
beta-Asp. Sequencing by Edman degradation does not proceed beyond the
beta-Asp and proceedes slowly through the aspartimide (good diagnostic
tools in conjunction with MS, chemical reversion, and Asp-N peptide
mapping). I know chemically why this should happen and can draw clear
diagrams, but I haven't been able to find a literature reference to the
Edman chemistry as it relates to the aspartimide. Has anyone run across
one that might be helpful? Are there any other amino acid modifications
that affect Edman degradation rates, but not the final PTH derivative?

Thanks for your help.
Paul Tressel