I don't know how you would get pyroglu, but you may have got succinimide
formation at the Asp-Gly bond, which would lead to M-18 and reopening of
the ring to give the starting peptide and the isoaspartyl peptide. See
R.C. Stephenson and S. Clarke, "Succinimide Formation from Aspartyl and
Asparaginyl Peptides as a Model for the Spontaneous Degradation of
Proteins."
J. Biol. Chem. 264, 6164-6170.
I'm not sure how to avoid this reaction.
Richard Laursen
----------------------------------------
>Hello everyone,
>
>I have synthesized a peptide with the sequence CDGSVWAQSESFPELK. The HPLC
>shows two major peaks adjacent to each other with the major peak being a
>dehydrated (-18) species of the peptide as shown by mass spec. I suspect
>pyroglu. formation, but I'm not sure where. Can anyone comment on what
>might have happened here and what I can do to prevent this if I need to
>resynthesize??
>
>Thanks in advance!
>
>Mary
>
>Mary Bower
>Instrument Specialist
>Purdue University
>Department of Biochemistry
>West Lafayette, IN 47907
>
>Phone (765)494-6540
>Fax (765)494-7897
>email; Bower@Biochem.purdue.edu
Richard A. Laursen
Department of Chemistry
Boston University
590 Commonwealth Ave.
Boston, MA 02215
Tel (617) 353-2491; FAX (617) 353-6466
email: <laursen@bu.edu>