Sigma-Aldrich Catalase from bovine liver

Catalase from bovine liver is an antioxidant enzyme that plays a critical role in cellular defense against oxidative damage. It catalyzes the decomposition of hydrogen peroxide (H₂O₂) into water and oxygen, thereby reducing the harmful effects of reactive oxygen species (ROS). The enzyme is a tetrameric protein consisting of four identical subunits, each weighing approximately 60 kDa, and contains iron as a cofactor within a protoheme IX group.

Key Features:

1. Structure:
   • Tetrameric enzyme with four subunits (60 kDa each).
   • Contains iron bound to protoheme IX group.
   • NADP is tightly bound within 13.7 angstroms of the heme group.
2. Activity and Unit Definition:
   • One unit decomposes 1.0 μmole of H₂O₂ per minute at pH 7.0 and 25°C.
   • Enzyme activity: 2,000–5,000 units/mg.
   • Measured by the decrease in absorbance at 240 nm (A240).
3. Solubility:
   • Soluble in 50 mM potassium phosphate buffer at a concentration of 1 mg/mL and pH 7.0.
4. Stability and Storage:
   • Storage Temperature: -20°C for the powdered form.
   • Caution: Solutions of catalase should not be frozen, as freezing results in a 50–70% loss of activity.
5. Inhibition:
   • Inhibited by compounds such as:
     • 3-amino-1-H-1,2,4 triazole.
     • Cyanide, azide, hydroxylamine, and cyanogen bromide.
     • Reducing agents like 2-mercaptoethanol and dithiothreitol.

Applications:

1. Research Applications:
   • Antioxidant Studies: Evaluate the roles of ROS in cellular processes like gene expression and apoptosis.
   • Oxidative Stress Studies: Protects proteins, lipids, and nucleic acids from oxidative damage.
   • Biocatalysis: Used to catalyze H₂O₂ degradation in biofuel cell development and other enzymatic reactions.
2. Industrial Applications:
   • Food Industry: Removal of hydrogen peroxide from milk and cheese.
   • Textile Industry: Used in textile bleaching processes.
   • Bioremediation: Mitigates oxidative stress in DNA-repair mutants of E. coli.
3. Specific Use Cases:
   • H₂O₂-O₂ Based Biocathodes: Prepare biocathodes for glucose biofuel cells.
   • Immobilized Enzyme Studies: Examine kinetic properties and storage stability of catalase immobilized on materials like Florisil.
   • Superoxide Generation Research: Utilize in glutathione-mediated superoxide generation in aqueous solutions.

Biochemical Properties:

1. Reactivity:
   • Catalyzes the conversion of H₂O₂ into H₂O and O₂.
   • Reacts with alkylhydrogen peroxides like methylperoxide and ethylperoxide.
   • Uses alternate hydrogen donors (e.g., methanol, ethanol, formate).
2. Cofactors:
   • Requires iron (Fe) or manganese (Mn) as cofactors.

Preparation and Usage Notes:

• Reconstitution:
  • Reconstitute in potassium phosphate buffer (pH 7.0) at 1 mg/mL concentration for optimal activity.
• Handling Precautions:
  • Avoid freezing reconstituted solutions to maintain enzyme activity.
  • Store powdered form at -20°C for long-term stability.

Unit Definition:

• One unit decomposes 1.0 μmole of H₂O₂ per minute at pH 7.0 and 25°C, as measured by the decrease in absorbance at 240 nm.

Storage Recommendations:

• Powder Form: Store at -20°C in a dry environment.
• Reconstituted Solutions: Do not freeze; store at 4°C for short-term use.

Sigma-Aldrich Catalase from bovine liver is a highly versatile enzyme with applications ranging from academic research to industrial processes. Its ability to mitigate oxidative stress makes it invaluable for studying ROS-mediated cellular effects, as well as practical applications in food processing, biofuel technology, and bioremediation efforts.