Glutathione is a tripeptide made of glutamate, cysteine and glycine, and it is one of the most abundant antioxidant molecules inside cells. It plays a central part in keeping the intracellular environment reduced, in neutralizing reactive oxygen species and in the enzymatic processing of many foreign compounds. PRIME supplies glutathione as a research material for laboratory use only.
What is glutathione?
Chemically, glutathione is gamma-L-glutamyl-L-cysteinyl-glycine. What sets it apart from an ordinary tripeptide is the first bond: glutamate is linked to cysteine through the carboxyl group on its side chain (the gamma carboxyl) rather than the usual alpha carboxyl. This gamma bond makes glutathione resistant to most peptidases. It is broken down instead by a specific enzyme, gamma-glutamyl transferase, which is part of how cells recycle it.
The functional heart of the molecule is the thiol (sulfhydryl) group on the cysteine residue. In its reduced form, written GSH, that thiol can donate electrons. When two GSH molecules are oxidized, they join through a disulfide bond to form glutathione disulfide, written GSSG. The ratio of GSH to GSSG is one of the most widely used markers of cellular redox state in research.
Cells make glutathione in two ATP-dependent steps. Glutamate-cysteine ligase first joins glutamate and cysteine, and this step is generally considered rate-limiting. Glutathione synthetase then adds glycine. The availability of cysteine is often a limiting factor, which is why cysteine precursors such as N-acetylcysteine are used in research on glutathione synthesis.
How glutathione works: mechanism studied in research
Glutathione acts both directly and as a cofactor for enzymes. The main systems studied are:
- Glutathione peroxidases: enzymes that use GSH to reduce hydrogen peroxide and lipid hydroperoxides, converting GSH to GSSG in the process. One member of this family, GPX4, protects membranes from lipid peroxidation and is central to research on ferroptosis, a regulated form of cell death.
- Glutathione reductase: the enzyme that regenerates GSH from GSSG using NADPH, linking glutathione status to the cell's NADPH supply.
- Glutathione S-transferases: a large enzyme family that attaches glutathione to electrophilic compounds, including many xenobiotics, as part of phase II detoxification, making them easier to export.
- Protein glutathionylation: reversible attachment of glutathione to cysteine residues on proteins, studied as a way cells protect and regulate proteins under oxidative stress.
- Direct scavenging: GSH can react non-enzymatically with some reactive species and helps regenerate other antioxidants.
Glutathione is also compartmentalized, with separate pools in the cytosol, mitochondria and endoplasmic reticulum, and researchers often measure these pools separately because they behave differently under stress.
Areas of research
- Oxidative stress models: glutathione depletion and supplementation are standard tools in cell and animal studies of oxidative damage.
- Mitochondrial redox biology: the mitochondrial glutathione pool has been studied in research on mitochondrial function and reactive oxygen species.
- Ferroptosis: the GSH and GPX4 axis is a major focus in research on this iron-dependent form of cell death.
- Xenobiotic metabolism: glutathione conjugation is studied in liver research and in the handling of drugs and environmental compounds in experimental systems.
- Aging and pigmentation research: glutathione levels have been examined in studies of aging tissues, and its role in melanin synthesis pathways has been investigated.
These are research areas, not established effects in people, and findings in cell or animal models do not transfer automatically.
Glutathione key facts
| Property | Detail |
|---|---|
| Compound class | Tripeptide antioxidant (thiol) |
| Structure | Gamma-L-glutamyl-L-cysteinyl-glycine, with a gamma peptide bond between glutamate and cysteine |
| Forms | Reduced (GSH) and oxidized disulfide (GSSG) |
| Key enzymes | Glutathione peroxidases, glutathione reductase, glutathione S-transferases |
| Form supplied | Lyophilized powder in a sealed vial (see product page for vial size) |
| Research status | Research material supplied for laboratory use only |
| Storage | Cold, dry, sealed and protected from light; refrigerate after reconstitution |
Handling and storage in the lab
Reduced glutathione is prone to oxidation, so handling is mostly about limiting exposure to air, heat, light and moisture. Keep unopened vials refrigerated, or frozen for longer-term storage, and let a cold vial reach room temperature before opening to avoid condensation.
For lab work, the powder is commonly reconstituted with bacteriostatic water or with a buffer suited to the assay. Swirl gently to dissolve. In solution, GSH gradually oxidizes to GSSG, and this happens faster at neutral to alkaline pH and in the presence of trace metal ions. For that reason, labs usually prepare solutions fresh, keep them refrigerated and protected from light, and avoid repeated freeze-thaw cycles. Label each vial with concentration and date so that the age of a solution is always clear when interpreting redox measurements.
Follow standard laboratory safety practice and your institution's procedures for chemical handling and disposal.
Quality and lab results
In redox research, the proportion of reduced to oxidized material in a reagent can affect results, so identity and purity matter. Every batch of glutathione sold by PRIME is tested by an independent laboratory, and the certificate of analysis for each lot is published on the lab results page. Match the COA to your lot number and keep it with your records.
Vial size and current batch information are listed on the glutathione product page.
Related research
- NAD+ research guide: the coenzyme family that includes NADPH, which glutathione reductase depends on.
- SS-31 (elamipretide) research guide: a mitochondria-targeted peptide studied in oxidative stress research.
- MOTS-c vs SS-31: two peptides studied in mitochondrial research, compared side by side.
Glutathione FAQ
Is glutathione a peptide?
Yes. Glutathione is a tripeptide made of glutamate, cysteine and glycine. It is unusual because glutamate is joined to cysteine through its side-chain gamma carboxyl group, which protects it from most peptidases.
What is the difference between GSH and GSSG?
GSH is reduced glutathione, the form with a free thiol group that can donate electrons. GSSG is oxidized glutathione, two molecules joined by a disulfide bond. The GSH to GSSG ratio is widely used in research as a marker of cellular redox balance.
What does glutathione do in cells?
In research it is described as a major intracellular antioxidant and enzyme cofactor. It supports glutathione peroxidases in reducing peroxides, is conjugated to foreign compounds by glutathione S-transferases, and helps maintain protein thiols under oxidative stress.
Why does glutathione oxidize in solution?
The cysteine thiol reacts with oxygen and other oxidants, especially at neutral to alkaline pH and in the presence of metal ions, converting GSH to GSSG. This is why fresh, cold, light-protected solutions are standard in the lab.
How should glutathione be stored?
Store the powder sealed, cold, dry and away from light. After reconstitution for lab use, keep the solution refrigerated and protected from light, prepare it fresh where possible and avoid repeated freeze-thaw cycles.
For laboratory research use only. Not for human consumption. Not a drug, food or cosmetic.