GLUTATHIONE

Description

Glutathione is a tripeptide with the sequence gamma-Glu-Cys-Gly and a molecular weight of 307.32 g/mol. It is supplied here in the reduced form, abbreviated GSH, and is among the most abundant small molecules in living cells.

The gamma linkage

Glutathione is not an ordinary peptide, and the difference is worth understanding before working with it.

In a standard peptide bond, the alpha-carboxyl group of one amino acid joins the amino group of the next. In glutathione, the glutamate connects through its side-chain carboxyl instead, forming what is termed an isopeptide or gamma linkage. Writing the sequence as Glu-Cys-Gly, without the gamma, describes a different molecule.

This has a direct functional consequence. Standard aminopeptidases and most proteases cannot cleave a gamma linkage, so glutathione resists the enzymatic degradation that would rapidly dismantle a conventional tripeptide. Its breakdown requires a specific enzyme, gamma-glutamyl transpeptidase. This is why a three-residue molecule can persist at millimolar concentrations inside cells.

Reduced and oxidised forms

The cysteine thiol group is where glutathione’s chemistry happens. Two glutathione molecules can join through a disulfide bond between their cysteines, forming the oxidised dimer GSSG.

GSH and GSSG are distinct compounds with different registry numbers and different masses: 307.32 for the reduced monomer, 612.63 for the oxidised dimer. The material supplied here is the reduced form. The ratio between the two is a standard measure of cellular redox state, so for any redox work, confirming which form you have is essential rather than incidental.

Research background

The literature is enormous and long-established, and glutathione is better described as a subject of basic biochemistry than as an experimental compound.

Core areas include its role as an electron donor in the reduction of peroxides by glutathione peroxidase, its function in phase II conjugation reactions by which cells process xenobiotics, its participation in protein S-glutathionylation as a post-translational modification, and its use as a redox buffer maintaining the intracellular thiol environment.

The GSH to GSSG ratio is widely used as an experimental readout of oxidative stress.

Storage and handling

Store the powder at 36 to 46 °F (2 to 8 °C), protected from light and air. Allow the container to reach room temperature before opening.

Use 307.32 g/mol for molar calculations on the reduced form.

Store solutions cold and protected from light. Avoid repeated freeze-thaw cycles.

Purity and verification

Each lot is analysed by an independent laboratory, with identity confirmed by mass spectrometry and purity by HPLC. Test scope varies by lot; consult the certificate for the lot you receive.

Compound Identity

CAS Number

70-18-8 (reduced form, GSH)

Molecular Formula

C₁₀H₁₇N₃O₆S

Molecular Weight

307.32 g/mol

Chain Length

3 amino acids (tripeptide)

Sequence

γ-Glu-Cys-Gly
Glutamate is linked through its side-chain carboxyl, not the α-carboxyl

Redox State

Reduced (GSH). The oxidized dimer GSSG is a distinct compound at 612.63 g/mol, CAS 27025-41-8.

Also Known As

L-glutathione reduced, GSH

Physical Form

White crystalline powder

Storage

36–46 °F (2–8 °C), protected from light and air

Chemical Structure