Thiol determination by DTNB and detergents

[Sell Biology]

"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.