Sigma-Aldrich™ Glutathione S-Transferase (GST) from equine liver is a high-quality, lyophilized enzyme preparation with a specific activity of ≥25 units/mg protein. GST enzymes constitute a major detoxification family found in mammals and other organisms. They play a central role in Phase II metabolism, catalyzing the conjugation of reduced glutathione (GSH) with structurally diverse hydrophobic compounds containing electrophilic centers.

This enzyme is supplied as a lyophilized powder containing Tris buffer, reduced glutathione, and EDTA to maintain enzyme stability and activity. With a molecular weight of 45–50 kDa and a protein content of ≥60%, this preparation is ideal for biochemical assays, toxicology studies, enzyme kinetics, xenobiotic metabolism research, and analytical standard applications.

Key Features & Benefits

High Specific Activity

• ≥25 units/mg protein, ensuring strong catalytic performance
• One unit conjugates 1 µmol of CDNB with GSH per minute at pH 6.5, 25°C
• Suitable for sensitive kinetic and mechanistic studies

Native Enzyme from Equine Liver

• Represents physiologically relevant isoform distribution
• Contains cytoplasmic isoenzymes belonging to α, μ, θ, σ, and π classes
• Useful for comparative studies between species and enzyme classes

Lyophilized, Stabilized Preparation

• Long-term stability at –20°C
• Contains Tris buffer, GSH, and EDTA for optimal reconstitution
• Ready for use in spectrophotometric and fluorometric assays

Versatile Use Across Multiple Fields

• Toxicology
• Pharmacology
• Enzymology
• Cell and molecular biology
• Plant biology
• Environmental biochemistry

Chemical & Regulatory Information

Biochemical & Physiological Role

Major Detoxification Enzyme

GST catalyzes the conjugation of reduced glutathione (GSH) with:

• Electrophilic xenobiotics
• Reactive intermediates
• Pesticides and herbicides
• Pharmaceutical compounds
• Endogenous byproducts of oxidative stress

These reactions detoxify reactive substrates and facilitate their elimination.

Isoenzyme Diversity

Cytoplasmic GST isoforms include:

• α (Alpha)
• μ (Mu)
• π (Pi)
• θ (Theta)
• σ (Sigma)

Each isoform displays unique substrate specificity and physiological roles.

Applications

1. Enzyme Activity Assays

• Standard enzyme for GST spectrophotometric assays
• CDNB conjugation monitoring
• Kinetic characterization

2. Cell & Molecular Biology

Used as:

• Buffer component for endothelial cell assays
• Enzyme standard in metabolic pathway studies
• Reagent for studying GSH conjugation in mammalian and plant systems

3. Toxicology & ADME Studies

• Xenobiotic metabolism
• Drug detoxification profiling
• Hepatotoxicity and oxidative stress research

4. Plant & Environmental Research

• Measurement of GSB-conjugate fluorescence in plant cells
• Analysis of detoxification pathways in plant stress responses

Ordering Information

Sigma-Aldrich™ Glutathione S-Transferase from equine liver is a high-activity, high-purity native enzyme widely used for detoxification studies, xenobiotic metabolism research, enzyme kinetics, cell biology experiments, environmental toxicology, and biochemical assays. Its robust activity, consistent quality, and reliable performance make it an essential reagent in enzymology and metabolism research environments.