Sounds like beta elimination from one Cys. Was the peptide at high pH?
Ken
Kenneth A. Walsh
E.W.Davie/ZymoGenetics Chair of Biochemistry
Box # 357350
University of Washington
Seattle WA 98195
walsh@u.washington.edu
Phone 206-543-1768
FAX 206-685-9231
On Mon, 6 Jul 1998, Bryan Dunbar wrote:
> Hi guys,
> I have been sequencing a 31-residue polypeptide which contains 6
> cysteines. The calculated mass from the sequence is 3491, assuming all
> the Cysteines are involved in disulphides, which by homology, is pretty
> definite. However, when we look at this thing in the Voyager, we always
> get a mass of 3457 - anybody have any bright ideas about this "loss" of
> 34??
> Best regards,
> Bryan.
> --
> Bryan Dunbar,
> Protein Facility,
> Room WT27,
> Department of Molecular & Cell Biology,
> University of Aberdeen,
> Polwarth Building,
> Foresterhill,
> Aberdeen,
> SCOTLAND.
> AB25 2ZD.
> TEL: 01224-273103
> FAX: 01224-273104
> e-mail; b.dunbar@abdn.ac.uk
>
>