Hi there,

My question is: What standard curves should be used while estimating Tot GSH and GSSG by kinetic method using GR enzyme mediated recyling with DTNB chromophore?

Actually I am following a nature protocol (link given below): where they have asked us to use GSH and GSSG standards to find the actual values for estimation of Tot GSH and GSSG respectively using the DTNB based enzyme recycling mentioned.

But since the assay is enzyme mediated are we not suppose to take the same substrate for the standards (GSSG) as that in the samples?

https://www.nature.com/articles/nprot.2006.378

Addition:

I actually read two other protocols- (1) Sigma protocol in which they have asked to take GSH standard for Total GSH estimation. There is no comment about GSSG estimation and its standards.

https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/418/394/cs0260bul.pdf

(2) Methods in Enzymology Vol-77 By Jakosby (1981) where they have simply stated that the Standard should be of GSSG for Tot GSH estimation assay. (I am pretty lost)