Good Luck,
Trudy Holyst
Peptide Core
Blood Research Institute
Blood Center of SE WI
Milwaukee, WI 53201
mtholyst@BCSEW.edu
-----Original Message-----
From: Christoph Turck [mailto:turck@itsa.ucsf.edu]
Sent: Wednesday, July 14, 1999 8:27 PM
To: Recipients of ABRF List
Subject: cysteine deprotection
A question for the peptide synthesis experts. We have a peptide with
two cysteine residues, whose side chains are protected with an SBut group.
The structure of the side chain therefore is CH2-S-S-But. So far we have
been unsuccessful to selectively remove the SBut groups using two
procedures that we found in the literature. One uses nBu3P in NMP/water
(9:1) and the other uses nBu3P in 0.1M ammonium acetate, pH
7.8/iso-propanol (1:1).
Can anybody recommend a procedure that will deprotect the cysteines
without affecting the other protecting groups in the peptide, which was
synthesized using the Fmoc chemistry? Our ultimate goal is to modify the
cysteine residues with palmitic acid moieties before we do the Tfa
deprotection and peptide cleavage from the resin.
Thanks,
Chris (turck@itsa.ucsf.edu)