Glutathione (GSH and GSSG)

Glutathione (GSH) is a tripeptide comprised of three amino acids L-cysteine, L-glutamic acid and glycine. It is involved in the development and maintenance of protein disulfide bonds , the transport of amino acids across cell membranes, and in detoxification. Since glutathione contains a thiol group, it serves as a major endogenous antioxidants in cells preventing damage by neutralizing reactive oxygen species such as free radicals and peroxides. Monitoring reduced and oxidized glutathione in biological samples is a useful tool for evaluating the redox and detoxification status of cells and tissues against oxidative and free radical mediated cell injury. While few reagents and assay kits are commercially available for quantifying glutathione, they are hindered by their lack of sensitivity and tedious protocols. Amplite™ Fluorimetric Glutathione assay offers a convenient and ultra-sensitive method for the quantification of glutathione in biological samples.

Amplite™ Fluorimetric Glutathione Assay

Glutathione GSH/GSSG Ratio

In healthy cells and tissues, glutathione exists in two states, reduced (GSH) and oxidized (GSSG). In the reduced state, GSH is a major tissue antioxidant that neutralizes reactive oxygen species. As a result of donating an electron, GSH itself becomes reactive and will readily react with other reactive GSH molecules to form GSSG. Additionally, reduced GSH provides reducing equivalents for the glutathione peroxidase (GPx) catalyzed reduction of lipid hydroperoxides to their corresponding alcohols and hydrogen peroxide to water. In the GPx catalyzed reaction, the formation of a disulfide bond between two GSH molecules forms GSSG. The enzyme glutathione reductase (GR) recycles GSSG to GSH while simultaneously oxidizing ?-nicotinamide adenine dinucleotide phosphate (?-NADPH2).

Monitoring reduced GSH and its ratio with oxidized GSSG may be used to evaluate the redox and detoxification status of cells and tissues in relation to the protective role of glutathione against oxidative and free-radical-mediated cell injury. Under normal conditions, the GSH redox couple in mammalian cells typically ranges in concentration from 1 – 10 nM, with resting cells having molar GSH:GSSG ratios exceeding 100:1. When cells are exposed to increased levels of oxidative stress, GSSG accumulates and the ratio of GSH/GSSG decreases to ratios as low as 10:1 and even 1:1. As such, monitoring GSH/GSSG levels in biological samples has become a useful tool in evaluating oxidative stress of cells and tissues, and cell injuries caused by free radicals.

Amplite™ Glutathione GSH/GSSG Ratio Assays

Table 1. Ordering Info for Amplite Glutathione Kits (P.O.T) Products