Dear Hanno
The peroxide method should work but as you have
discovered you cannot let the treatment go for too long. Access to a mass
spec is useful as you could follow the reaction at suitable intervals (10
min) and I would suggest HPLC prepping the product immediately. Another
method which would be slower is stirring the peptide in a 20% DMSO/25mM
ammonium acetate (pH6.5) and following by RP HPLC. The speed of the reaction
will be dependent on the peptide sequence. Even if the reaction does not go
to completion the Met[O] peptide will elute earlier and will be separable by
RP HPLC
Good luck
Denis Scanlon
><html><div>Hi there,</div>
><div>is there any protocol available to oxidise the methionine residue in
>peptides in a controlled way so that only the sulfoxide is obtained. I
>tried hydrogenperoxide (3%) and performic acid but in both cases I ended
>up with the sulfonyl compound (the dioxide). Any suggestions are
>appreciated.</div>
><div>Thanks in advance,</div>
>Hanno
><br>
>
><br>
>__________________<br>
><br>
>Hanno Steen<br>
><br>
>Protein Interaction Laboratory (PIL) <br>
>Department of Biochemistry and Molecular Biology <br>
>University of Southern Denmark<br>
>Campusvej 55 <br>
>5230 Odense M <br>
>Denmark<br>
>Phone: +45-65502474 (office), +45-65502470 (lab), +45-65502435
>(MS-lab)<br>
>Fax: +45-65933018 <br>
>email hanno.steen@cebi.sdu.dk<br>
>URL http//<font color="#0000FF"><u>www.pil.sdu.dk<br>
></font></u></html>
>
>
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