Thiol determination by DTNB and detergents

[SB]

Sell Biology wrote:

> "SB" <biswas.16 at osu.edu> wrote:
> 
> > Hi
> > 
> > Does anyone know what effect detergents (eg: SDS at 10 or 15%) have
> > on the measurement of thiol concentration using DTNB?
> 
> I would guess none after checking PubMed with the search "DTNB AND
> SDS AND interference" and coming up with 0 items.
> 
> But if it's really a worry for you, there are ways of precipitating
> excess SDS in solution merely by adding potassium salts (K-SDS is
> insoluble, as I recall), mixing, probably at cold temperatures,
> spinning it out and getting the supernatant.
> 
> Assay a sample of your thiol-containing material (protein?) with the
> excess SDS present and a sample in which you've tried to remove the
> excess, and compare the results (do replicates at two or three levels
> for getting a good assessment of potential negative interferences).
> Your question on interference will then be answered.

Thanks for your suggestion. Actually I was thinking of whether it will
be possible to solubilize cells with detergent and then use DTNB to
estimate thiol content. All studies on thiol determination use acid
precipitation of proteins and estimating thiols in the acid soluble
supernatant. I welcome any input regarding this matter.

SB