If this does not work then Trudy Holysts suggestion of resynthesis and the
use ofCys(Mtt) is a good one
Regards
Denis Scanlon
Auspep P/L
>Hello Christopher, I would resynthesize using Fmoc-Cys(Mmt)-OH (from
>Novabiochem) and then you can selectivley remove the protecting group using
>weak acid (consult the catalog for exact procedure)leaving the rest of the
>peptide with the protecting groups intact. I have not personally used this
>protecting group but have done similar strategies with Lys(Mtt) with great
>success.
>
>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)
>
>
>