assay for free cysteines

Petter petter at
Thu Apr 2 21:40:46 EST 1998

In article <35237E42.4625143F at>, Yu Wai Chen
<ywc at> wrote:

>Dear all,
>I would like to know if the 6 cysteines of my protein is
>disulphide-bridged or not.  Can some one point me to a good reference or
>protocol how to achieve this?  I've heard that we can use Ellman's
>reagent to do it...  Is Ellman's reagent good for buried cysteines as
>well?  Thanks.

Ellman's will quantify cys residues that are both free and accessible, you
can always denature
 and quantify to  get the buried ones...

>Yu Wai CHEN, Ph.D. ..................  email: ywc at
> Centre for Protein Engineering,              tel: 44-(1223) 402148
> MRC Centre, Cambridge  CB2 2QH, U.K.         fax: 44-(1223) 402140
> WWW homepage:

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