Asp-N cleavage

Robert Donnelly (donnelly@umdnj.edu)
Thu, 20 Aug 1998 18:39:26 -0400

Hello all,
I recently cut a protein that is N-terminally blocked with B-M Asp-N, isolated peptides by HPLC and sequenced four peaks. Since I was expecting Asp as the N terminal amino acid I was surprised to find that three of the peptides gave a clear Ala as the N terminal amino acid. Does anyone know an explanation for this? Does Asp-N also modify the N terminus or alter the Asp itself?
Thanks for your responses.
Bob