What is L-GLUTATHIONE?
L-Glutathione, commonly abbreviated GSH, is a low-molecular-weight tripeptide classified within the broader family of gamma-glutamyl peptides. It carries the molecular formula C10H17N3O6S and a molecular weight of 307.32, and is registered under CAS number 70-18-8. As a three-amino-acid peptide, it is among the smallest naturally distributed peptides characterized in cellular biochemistry.
Structurally, L-Glutathione is a linear tripeptide composed of L-glutamic acid, L-cysteine, and glycine. Its defining feature is an atypical gamma-peptide bond formed between the gamma-carboxyl group of the glutamate side chain and the amino group of cysteine, rather than the conventional alpha-peptide linkage found in most peptides. The cysteine residue contributes a free sulfhydryl (thiol) group, which is the redox-active moiety of the molecule; the full sequence is confirmed per the accompanying certificate of analysis. This unusual gamma linkage confers resistance to cleavage by standard aminopeptidases and is central to the molecule's identity as a reference standard.
In the scientific literature, L-Glutathione is a widely studied model compound in redox biology, oxidative-stress research, and thiol-chemistry investigations conducted in vitro. It is frequently employed as a reference analyte and as a substrate or ligand in enzymatic and analytical research models. This material is offered strictly for laboratory research use only; it is not a drug, dietary supplement, or medical product, and no physiological or therapeutic properties are described or implied.
Reconstitution & handling
L-Glutathione is supplied as a lyophilized or crystalline solid and is readily soluble in water and aqueous buffers, reflecting its polar, highly hydrophilic character. For reconstitution in a research setting, sterile or ultrapure water is a common vehicle, and mildly acidic to neutral buffers are also compatible with the free acid form. The solid should be brought to room temperature before opening to limit condensation, and solvent should be added gently against the vial wall, followed by slow swirling rather than vigorous vortexing to promote full dissolution.
Because the cysteinyl thiol is the redox-active center, prepared solutions are sensitive to oxidation; the free thiol can oxidize to the disulfide dimer (GSSG) in the presence of dissolved oxygen, elevated pH, and trace metal ions. Working solutions are therefore typically prepared fresh, handled under minimized headspace, and kept cold and protected from light during use. Reconstitution parameters should be selected according to the requirements of the specific analytical or in-vitro protocol.
Storage & stability
In lyophilized form, L-Glutathione is stable when stored sealed, desiccated, and protected from light, typically under refrigeration or freezer conditions for long-term storage. Once reconstituted, aqueous solutions are considerably less stable due to progressive thiol oxidation and should be stored cold, used promptly, and aliquoted to avoid repeated freeze-thaw cycles that can accelerate degradation. Minimizing exposure to air, elevated temperature, alkaline pH, and metal-ion contamination helps preserve the reduced (GSH) state during storage.
How it's tested
Identity and purity of L-Glutathione are established by reversed-phase high-performance liquid chromatography (HPLC), which resolves the tripeptide from related impurities including its oxidized disulfide form and confirms a purity of greater than or equal to 99 percent. Mass spectrometry is used to verify molecular identity against the expected mass consistent with the C10H17N3O6S formula and 307.32 molecular weight. Each lot is accompanied by a certificate of analysis (COA) documenting chromatographic purity, mass-spectral confirmation, and the verified peptide sequence, providing traceable analytical characterization for research reference use.