GSH GSSG Microplate Assay
The GSH GSSG Microplate Assay is For Research Use Only
Size: 1 x 96 wells
Sensitivity: 0.1 µM
Standard Range: 0.1 – 3 µM
Incubation Time: 20 minutes
Sample Type: Biological Fluids
Sample Size: 500 µl
Product Developed and Manufactured in the USA
The low concentration of GSSG (high GSH/GSSG ratio) in tissues coupled with the need to prevent GSH oxidation during sample preparation, are important considerations for the accurate measurement of GSSG and GSH/GSSG ratios. Guntherberg and Rost (2) first reported the use of N-ethylmaleimide (NEM) reacting with GSH to form a stable complex, therefore removing the GSH prior to the quantification of GSSG in tissues. Unfortunately, NEM inhibits GR. To overcome this problem, Griffith (3) employed 2-vinylpyridine (2-VP) to derivatize GSH. Although 2-VP does not significantly inhibit GR, it reacts relatively slowly with GSH and is not very soluble in aqueous solutions.
Scavenging of Free Thiols: GSH / GSSG Microplate Assay Kit employs a pyridine derivative as a thiol-scavenging reagent thereby overcoming the shortfalls of both prior methods. At the concentration employed in the assay, this derivative reacts quickly with GSH but does not interfere with the GR activity.
Thiol Quantification: The quantitative determination of the total amount of glutathione (GSH + GSSG) employs the enzymatic method first reported by Tietze (1). Briefly, the reaction of GSH with Ellman’s reagent (5,5′-dithiobis-2-nitrobenzoic acid (DTNB)) gives rise to a product that can be quantified spectrophotometrically at 412 nm. This reaction is used to measure the reduction of GSSG to GSH. The rate of the reaction is proportional to the GSH and GSSG concentration.