[uglepik]

I'm starting up my first peptides containing methionine and (eventually) cysteine. With regards to methionine I am a little unsure as to what to expect with regards to oxidation of the thioether (since it is not protected). As I am using Fmoc chemistry I have been told by more experienced lab mates that oxidation is not a problem, but in Fmoc Solid Phase Peptide Synthesis (Chan) it is written that oxidation to methionine sulphoxide can occur (page 78).

If anyone has experience with methionine (and alternatively cysteine) on solid-phase I'd like to hear your thoughts. How careful do I have be? Is argon atmosphere necessary? How do I reduce back to methionine if oxidation occurs? etc...

Thanks!

[Honclbrif]

Selective Oxidation and Reduction of Methionine Residues Peptides and Proteins by Oxygen Exchange between Sulfoxide and Sulfide

Journal of Biological Chemistry Vol. 261, No. 1.  pp. 66-70, 1986