RE: joining the mailing list

Marcus Macht (Marcus.Macht@uni-koeln.de)
Thu, 15 Jul 1999 09:11:46 +0100

At 18:27 14.07.99 -0700, you wrote:
>
> 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

Dear Christoph,

a former colleague of mine worked on the synthesis and palmitoylation of a
cystein containing peptide. She made the deprotection using
beta-mercaptoethanol/DMF (1:1, v/v) during 24 hat r.t. The resin was
subsequently washed withCH2Cl2, DMF, ethanol and ether and dried
afterwards. Additional protection groups in the peptide were Trt, Pmc and Boc.
For further details you can have a look into: "Synthesis and structural
characterization of human-identical lung surfactant
SP-C protein", Mayer-Fligge P et al, Pept Sci 1998 Aug;4(5):355-63.
I hope this helps.

Yours sincerely,
Marcus Macht
******************************************************************
Dr. Marcus Macht
ZMMK-Servicelabor
Joseph-Stelzmann-Str. 52
50931 Koeln
Tel.: +49 221 478-6995
Fax: +49 221 478-6977
e-mail: Marcus.Macht@uni-koeln.de
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