Catalase from Aspergillus niger

Research area: Cell Signaling

Catalase is an active enzyme present in aerobic organisms. It is a ferric hemoprotein and a tetramer.

Catalase from Aspergillus niger has been used:

• as a positive control during the functional characterization of Clostridium difficile spore coat proteins.
• as a component of the catalase solution to prepare GLOX buffer with enzymes to maintain the embryos of Caenorhabditis elegans before single-molecule fluorescence in situ hybridization (smFISH) studies
• as a component of the imaging buffer for stochastic optical reconstruction microscopy (STORM) imaging of platelet-rich plasma
• as a supplement in Todd Hewitt media plus 0.5 % yeast extract (THY) media for the neutralization of pneumococcal H₂O₂

Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen. Each subunit of the tetramer contains iron bound to a protoheme IX group. The enzyme also strongly binds NADP, which is in close proximity to the heme group. Isoelectric point is found to be 6.5. Optimum pH for catalytic activity is 7.0. The enzyme activity is inhibited by 3-amino-1-H-1,2,4 triazole, cyanide, azide, hydroxylamine, cyanogen bromide, 2-mercaptoethanol, dithiothreitol, dianisidine, and nitrate. Incubation of catalase with ascorbate or ascorbate/Cu²⁺ results in degradation of the catalase molecule.

Catalase is involved in catalyzing the degradation of hydrogen peroxide (H₂O₂) to water and free oxygen. Catalase is used commercially for decomposing H₂O₂ as it is added as an antimicrobial agent in process streams. It also catalyzes the oxidation of electron donors like ethanol and phenols during lower concentrations of H₂O₂. Catalase shows antioxidant activity by protecting cells from higher levels of reactive oxygen species (ROS). Increased expression of catalase is observed in chronic lymphocytic leukemia, gastric cancer, glioma, and melanoma. Decreased levels of catalase are seen in acute myeloid leukemia, lung, pancreatic, prostate, and skin (non-melanoma) cancers. Hence catalase exhibits a dual role in cancer.

Suspension in 3.2 M (NH₄)₂SO₄ solution, pH 6.0

Protein determined by biuret

One unit will decompose 1.0 μmole of H₂O₂ per min at pH 7.0 at 25 °C, while the H₂O₂ concentration falls from 10.3 to 9.2 mM, measured by the rate of decrease of A₂₄₀.

Freezing of solutions is not recommended.