FW: cysteines

Everson, Anita [PRI] (AEverson@prius.jnj.com)
Fri, 27 Mar 1998 13:19:46 -0500

Under acidic (HOAc and TFA) conditions, we use TCEP-HCl
(Tris(2-Carboxyethyl)-Phosphine Hydrochloride) from Pierce, Cat. No.
20490. It does a great job of reducing cysteines in acid; it's like a
DTT for acidic conditions. If you're worried about dimerization on the
column, you could use it in your HPLC buffers. To remove it from your
sample, just desalt on an HPLC column--it comes out in the void.

Anita Everson
RW Johnson PRI, La Jolla, CA
Peptide Lab
aeverson@prius.jnj.com

> ----------
> From: jholt@voicenet.com[SMTP:jholt@voicenet.com]
> Sent: Thursday, March 26, 1998 4:22 PM
> To: Recipients of ABRF List
> Subject: cysteines
>
> Does anyone have an idea how I might keep cysteines reversibly reduced
> during a purification using reverse phase HPLC under the usual 0.1%
> TFA
> conditions?? I know traditional alkylation works, and allows me to
> achieve
> the purification, and I know reduction and hoping
> -that-reoxidation-won't-occur-upon-lowering-the-pH and proceeding,
> doesn't.
>
> John Holt
>
> Pasteur Merieux Connaught
>
>