Mary Kay,
I just synthesized such a peptide. After purification, I added 10 fold excess
(by weight) of free Cys and suspended the peptide in 30 % DMSO 3 hrs. The
disulfide formation can be monitored by HPLC. Of course this will also make
cys-cys dimers but their retention time will be different and can easily be
separated from the desired product. Check out the paper by Tam et al. J.Am Chem
Soc. 1991, 113, 6657-6662 on disulfide formation using DMSO.
Hope this helps,
Trudy Holyst
Peptide Core Lab
Blood Center of SE WI
Milwaukee, WI
mtholyst@smtpgate.bcsew.edu
______________________________ Reply Separator _________________________________
Subject: Peptide Synthesis question
Author: Mary Kay Dolejsi <marykay@fred.fhcrc.org> at smtpgate
Date: 9/28/98 10:02 AM
Hello all,
We've just gotten a request for synthesis of a 9 residue peptide, with one
Cys in the chain, and they would like it linked through a disulfide to a
free cys, not part of any peptide chain. The peptide itself seems
straightforward to make, but how would you best go about making the
disulfide with free Cys? Just throw in Cys after cleavage and
deprotection, and hope for the best? How about purification?
Any thoughts, suggestions, or experience will be greatly appreciated.
Mary Kay Dolejsi, Ph.D.
Manager, Biotech lab
marykay@fred.fhcrc.org
phone: 206-667-4470
fax: 206-667-6497
Mail address:
Fred Hutchinson Cancer Research Center
1100 Fairview Ave N., B1-080
PO Box 19024
Seattle, WA 98109-1024