Glutathione Colorimetric Detection Kit (Invitrogen™)

The Glutathione Detection research-use-only kit is a colorimetric assay designed for the quantification and detection of glutathione in whole blood, serum, plasma, erythrocytes, urine, cell lysates and tissue samples.

This complete, ready-to-use kit includes clear 96-well plate(s), glutathione standard, assay buffer, and other components to perform the assay. A 96-well microplate reader capable of reading optical absorption at 405-412 nm is required for use of this kit.

Performance characteristics
• Assay type: colorimetric detection kit
• Sample types: whole blood, serum, plasma, erythrocytes, urine, cell lysates, and tissue samples
• Sensitivity: 0.634 μM
• Standard curve range: 0.78–25 μM
• Reactivity: species independent

Background
Glutathione (GSH) is the highest concentration non-protein thiol in mammalian cells and is present in concentrations of 0.5–10 mM. GSH plays a key role in many biological processes, including the synthesis of proteins and DNA, the transport of amino acids, and the protection of cells against oxidation. Harmful hydrogen peroxide cellular levels are minimized by the enzyme glutathione peroxidase (GP) using GSH as a reductant. The oxidized GSH dimer, GSSG, is formed from GSH and peroxide by the GP reaction. An important role of GSSG in the NFkB activating signal cascade is suggested by the facts that the potent NFk B inducer, tetradecanoyl phorbol acetate, increases intracellular GSSG levels and GSSG/GSH ratios. Glutathione S-transferases (GST) are an important group of enzymes that catalyze the nucleophilic addition of GSH to electrophiles. They are encoded by 5 gene families; 4 encode cytosolic GST and one encodes the microsomal form of GST.

Assay principle
The Glutathione Colorimetric Detection Kit is designed to quantitatively measure glutathione (GSH), and oxidized glutathione (GSSG) present in a variety of samples. No separation or washing is required. A GSSG standard is provided to generate a standard curve for the assay and all samples should be read off the standard curve. The kit utilizes a colorimetric substrate that reacts with the free thiol group on GSH to yield a highly colored product. Supplied reagents are in solution and require simple dilution for use in the assay. By using 2-vinylpyridine (not supplied) to block any free GSH in the sample, oxidized glutathione (GSSG) can be determined. Any samples that have not been treated with 2-vinylpyridine will yield Total GSH levels. The Free GSH concentration in the sample is calculated from the difference between the Total GSH determined and the GSH generated from oxidized glutathione for the 2-vinylpyridine-treated samples. The concentration of GSH can be determined either as an endpoint read of the color developed at 405 nm or by measuring the rate of color development at 405 nm.

Related links
Learn more about ELISA kits
Learn more about other immunoassays