The short version of GSH fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-15. Anything still debated is marked as such rather than presented as settled.
Measuring glutathione in biological samples requires attention to oxidation and matrix effects. High-performance liquid chromatography with ultraviolet or fluorescence detection can separate reduced and oxidized forms after derivatization. Liquid chromatography with tandem mass spectrometry offers higher specificity and can quantify glutathione alongside related thiols. Because glutathione can oxidize during sample handling, many protocols use rapid acidification with metaphosphoric acid or sulfosalicylic acid. Internal standards help correct for losses during extraction and analysis.
Enzymatic recycling assays provide a complementary approach for total glutathione. In these methods, glutathione reductase reduces oxidized glutathione while a thiol-reactive reagent, such as 5,5'-dithiobis(2-nitrobenzoic acid), produces a colored product. The reaction cycles between reduced and oxidized forms, amplifying the signal. Spectrophotometric or fluorometric detection can then estimate concentration. Distinguishing reduced glutathione from glutathione disulfide often requires separate aliquots, masking agents, or chromatographic separation, and the choice affects reported values.
Glutathione is a small tripeptide built from glutamic acid, cysteine, and glycine. Its peptide bond between glutamate and cysteine involves the gamma-carboxyl group rather than the usual alpha-carboxyl group. This structure gives the molecule a reactive thiol on the cysteine residue. The reduced form, often abbreviated GSH, is the predominant intracellular species in many cell types. Because the thiol can donate electrons, glutathione participates in redox chemistry and in the conjugation of reactive molecules.
Cells synthesize glutathione through two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine, and glutathione synthetase adds glycine to form the complete tripeptide. Breakdown occurs through gamma-glutamyl transpeptidase and subsequent peptidase reactions, forming the gamma-glutamyl cycle. Within cells, glutathione also forms a disulfide-linked dimer called GSSG when two GSH molecules react. The balance between GSH and GSSG is widely used as an indicator of oxidative conditions, although the ratio can vary by compartment and tissue.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C | Desiccated, protected from light |
| Solution stability | Hours to days at neutral pH | Acidic pH and low oxygen slow oxidation |
| Oxidized form | Glutathione disulfide (GSSG) | Formed by thiol oxidation |
| Typical analytical method | LC-MS/MS or enzymatic recycling | Choice depends on matrix and specificity |
| Thiol pKa | Approximately 9.2 | Influences reactivity at physiological pH |
Common analytical approaches include enzymatic recycling assays, high-performance liquid chromatography, and mass spectrometry. Enzymatic recycling measures total glutathione after converting GSSG back to GSH, while separation methods can quantify GSH and GSSG separately. Derivatization may be used to improve detection or stability during analysis. LC-MS/MS offers high specificity and can distinguish glutathione from related thiols and adducts. Each method has different sensitivity, throughput, and susceptibility to interference, so method selection depends on the study question and sample matrix.
For solid glutathione reagents, storage at low temperature and protection from moisture and light are typical precautions. Aqueous solutions can oxidize over time, and pH affects stability; alkaline conditions generally promote thiol oxidation. Some protocols prepare fresh solutions, while others use antioxidants or chelators to limit metal-catalyzed oxidation. Purity and counterion content can vary among commercial preparations, affecting concentration calculations. Certificates of analysis and validated assays help verify identity and purity.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group. This unusual linkage protects the molecule from many common peptidases. The cysteine side chain carries a thiol group that can undergo reversible oxidation. Because of this thiol, glutathione participates in redox reactions and helps maintain the reducing environment inside most cells in living systems.
In cells, glutathione exists mainly in a reduced form called GSH. When two GSH molecules react, they form oxidized glutathione, or GSSG, which contains a disulfide bond. The ratio of GSH to GSSG is often used as an indicator of oxidative stress. Enzymes such as glutathione peroxidase and glutathione reductase help cycle the molecule between these two states. This cycling supports antioxidant defense, detoxification of reactive molecules, and regulation of certain signaling pathways.
Glutathione is present in most tissues, with especially high concentrations in the liver. It also serves as a cofactor for some enzymes and helps transport amino acids across cell membranes. In plants and microorganisms, glutathione contributes to stress responses and metal handling. The molecule is synthesized in two ATP-dependent steps, first producing gamma-glutamylcysteine and then adding glycine. Because cysteine availability often limits synthesis, dietary and metabolic factors can influence glutathione levels. Research continues to examine how these levels relate to health and disease.
== Detektoren == UV/VIS-Detektor Diodenarraydetektor (DAD) Multiwellenlängendetektor (MWD) Lichtstreudetektor Fluoreszenzdetektor Brechungsindexdetektor Massenspektrometer Leitfähigkeitsdetektor Elektrochemischer Detektor: Amperometrie, Coulometrie Radioaktivitäts-Detektor Stickstoffselektiver Detektor
== Literatur == Gaby Aced, Hermann J. Möckel: Liquidchromatographie – Apparative, theoretische und methodische Grundlagen der HPLC, VCH, Weinheim 1991, ISBN 3-527-28195-9 Heinz Engelhardt (Hrsg.): Practice of High Performance Liquid Chromatography. Applications, Equipment and Quantitative Analysis. Springer, Berlin u. a. 1986, ISBN 3-540-12589-2. Hans Henke: Flüssig-Chromatographie. Analytische und präparative Trennungen. Vogel-Buchverlag, Würzburg 1999, ISBN 3-8023-1757-2. Henk Lingeman, Willy J. M. Underberg (Hrsg.): Detection-Oriented Derivatization Techniques in Liquid Chromatography (= Chromatographic Science. Bd. 48). Marcel Dekker Inc., New York NY u. a. 1990, ISBN 0-8247-8287-9. Reinhard Matissek, Reiner Wittkowski (Hrsg.): High Performance Liquid Chromatography in Food Control and Research. Behr’s Verlag, Hamburg 1992, ISBN 3-86022-029-2. Veronika R. Meyer: Fallstricke und Fehlerquellen der HPLC in Bildern. Hüthig GmbH, Heidelberg 1995, ISBN 3-7785-2417-8. Lloyd R. Snyder, Joseph J. Kirkland, John W. Dolan: Introduction to Modern Liquid Chromatography. 3rd Edition. John Wiley & Sons, Hoboken NJ 2010, ISBN 978-0-470-16754-0.
Petrolether ist ein farbloses Gemisch verschiedener gesättigter Kohlenwasserstoffe (üblicherweise Alkane wie Pentan und Hexan). Es handelt sich also nicht um einen Ether im Sinne der allgemeinen chemischen Nomenklatur. Die Bezeichnung „Ether“ hebt auf die ähnlich hohe Flüchtigkeit wie der von Diethylether ab.
Sources: de.wikipedia.org
== Verwendung == Petrolether sind aromatenarme, niedrig siedende (zwischen ca. 25 °C und 80 °C), leichtentzündliche Kohlenwasserstoff-Fraktionen. Sie werden verwendet bei Verfahren, bei denen eine schnelle, leichte (d. h. auch energiesparende) Verdampfung des Lösungsmittels gewünscht ist. Die Anforderungen sind in der Norm DIN 51630 geregelt. Petrolether findet in der organischen Chemie als Lösungsmittel und in der Chromatographie als mobile Phase Verwendung.
Sources: de.wikipedia.org
Chromatographic methods can separate the two forms before detection. Enzymatic assays often measure total glutathione first and then use a separate procedure to estimate the oxidized fraction. The difference between total and oxidized amounts provides an indirect estimate of the reduced form.
Acidification lowers pH and slows thiol oxidation during handling. It also helps precipitate proteins that could interfere with detection. Typical choices include metaphosphoric acid and sulfosalicylic acid.
Dissolved oxygen reacts with the thiol group, forming glutathione disulfide. Neutral and alkaline conditions generally increase the oxidation rate. Light, metal ions, and repeated freezing and thawing can also reduce stability.
It is a tripeptide of glutamic acid, cysteine, and glycine. The linkage between glutamate and cysteine uses the gamma-carboxyl group, which is unusual for peptides.