* Catalase test on nutrient agar tests for the production of catalase enzyme, which splits hydrogen peroxide and releases oxygen gas.

Catalase is a tetramer of four polypeptide chains, each over 500 amino acids long .< ref name = Boon_a > It contains four porphyrin heme ( iron ) groups that allow the enzyme to react with the hydrogen peroxide.

Catalase was first noticed in 1818 when Louis Jacques Thénard, who discovered H < sub > 2 </ sub > O < sub > 2 </ sub > ( hydrogen peroxide ), suggested its breakdown is caused by an unknown substance.

Catalase can also catalyze the oxidation, by hydrogen peroxide, of various metabolites and toxins, including formaldehyde, formic acid, phenols, acetaldehyde and alcohols.

Catalase is used in the food industry for removing hydrogen peroxide from milk prior to cheese production.

Catalase is also used in the textile industry, removing hydrogen peroxide from fabrics to make sure the material is peroxide-free.

Catalase is an enzyme that catalyzes the breakdown of hydrogen peroxide in many organisms.

Catalase, which is concentrated in peroxisomes located next to mitochondria, reacts with the hydrogen peroxide to catalyze the formation of water and oxygen.

USML-2 Experiments included: the Surface Tension Driven Convection Experiment ( STDCE ), the Drop Physics Module, the Drop Dynamics Experiment ; the Science and Technology of Surface-Controlled Phenomena experiment ; the Geophysical Fluid Flow Cell Experiment ; the Crystal Growth Furnace, the Orbital Processing of High Quality Cadmium Zinc Telluride Compound Semiconductors experiment ; the Study of Dopant Segregation Behavior During the Crystal Growth of Gallium Arsenide ( GaAs ) in Microgravity experiment ; the Crystal Growth of Selected II-VI Semiconducting Alloys by Directional Solidification experiment ; the Vapor Transport Crystal Growth of Mercury Cadmium Tellurida in Microgravity experiment ; the Zeolite Crystal Growth Furnace ( ZCG ), the Interface Configuration Experiment ( ICE ), the Oscillatory Thermocapillary Flow Experiment ; the Fiber Supported Droplet Combustion Experiment ; the Particle Dispersion Experiment ; the Single-Locker Protein Crystal Growth experiment ; ( including the Protein Crystallization Apparatus for Microgravity ( PCAM ) and the Diffusion-controlled Crystallization Apparatus for Microgravity ( DCAM )); the Crystal Growth by Liquid-Liquid Diffusion, the Commercial Protein Crystal Growth experiment ; the Advanced Protein Crystallization Facility, Crystallization of Apocrystacyanin C experiment ; Crystal Structure Analysis of the Bacteriophage Lambda Lysozyme, Crystallization of RNA Molecules Under Microgravity Conditions experiment ; Crystallization of the Protein Grb2 and Triclinic Lysozyme experiment ; Microgravity Crystallization of Thermophilic Aspartyl-tRNA Synthetase and Thaumatin experiment ; Crystallization in a Microgravity Environment of CcdB experiment ; A Multivariate Analysis of X-ray Diffraction Data Obtained from Glutathione S Transferase experiment ; Protein Crystal Growth: Light-driven Charge Translocation Through Bacteriorhodopsin experiment ; Crystallization of Ribosome experiment ; Crystallization of Sulfolobus Solfataricus Alcohol Dehydrogenase experiment ; Crystallization of Turnip Yellow Mosaic Virus, Tomato Aspermy Virus, Satellite Panicum Mosaic Virus, Canavalin, Beef Liver Catalase, Concanavalin B experiment ; Crystallization of the Epidermal Growth Factor ( EGF ); Structure of the Membrane-Embedded Protein Complex Photosystem I ; Crystallization of Visual Pigment Rhodopsin ; Commercial Generic Bioprocessing Apparatus ; Astroculture Facility and Experiment.

Catalase is a common enzyme found in nearly all living organisms exposed to oxygen.

Catalase reactions vary among Enterobacteriaceae.

Catalase is usually located in a cellular, bipolar environment organelle called the peroxisome.

Catalase contributes to ethanol metabolism in the body after ingestion of alcohol, but it only breaks down a small fraction of the alcohol in the body.

Catalase is also universal among plants, and many fungi are also high producers of the enzyme.

Catalase has been shown to interact with the ABL2 and Abl genes.

Although oxidation reactions are crucial for life, they can also be damaging ; plants and animals maintain complex systems of multiple types of antioxidants, such as glutathione, vitamin C, and vitamin E as well as enzymes such as catalase, superoxide dismutase and various peroxidases.

After only 30 days of taking the tea daily researchers found Lemon balm tea resulted in a significant improvement in plasma levels of catalase, superoxide dismutase, and glutathione peroxidase and a marked reduction in plasma

In higher plants, peroxisomes contain also a complex battery of antioxidative enzymes such as superoxide dismutase, the components of the ascorbate-glutathione cycle, and the NADP-dehydrogenases of the pentose-phosphate pathway.

Irwin Fridovich and Joe McCord first discovered and established their superoxide dismutase activity.

Likewise, Brewer ( 1967 ) identified a protein that later became known as superoxide dismutase as an indophenol oxidase by protein analysis of starch gels using the phenazine-tetrazolium technique.

Thus, there are three major families of superoxide dismutase, depending on the metal cofactor: Cu / Zn ( which binds both copper and zinc ), Fe and Mn types ( which bind either iron or manganese ), and the Ni type, which binds nickel.

However, C. botulinum tolerates traces of oxygen due to the enzyme superoxide dismutase ( SOD ) which is an important antioxidant defense in nearly all cells exposed to oxygen.

Insulin resistance has been proposed at a molecular level to be a reaction to excess nutrition by superoxide dismutase in cell mitochondria that acts as an antioxidant defense mechanism.

It is also based on the finding that insulin resistance can be rapidly reversed by exposing cells to mitochondrial uncouplers, electron transport chain inhibitors, or mitochondrial superoxide dismutase mimetics.

Copper is needed by the body for a number of functions, predominantly as a cofactor for a number of enzymes such as ceruloplasmin, cytochrome c oxidase, dopamine β-hydroxylase, superoxide dismutase and tyrosinase.

In turn, micro-organisms genetically engineered to lack superoxide dismutase ( SOD ), lose virulence.

Because superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide scavenging enzyme, superoxide dismutase, or SOD.

Formulations of superoxide dismutase are also reported to be effective in Peyronie's disease.

Structure of a human superoxide dismutase 2 tetramer

The superoxide dismutase enzymes perform this function very efficiently.

The superoxide dismutase group of enzymes, abbreviated as SOD, increase the rate of reaction to near the diffusion limited rate.

This enzyme also contains zinc ions for stabilization and is activated by copper chaperone for superoxide dismutase ( CCS ).

** Minor enzymes include salivary acid phosphatases A + B, N-acetylmuramoyl-L-alanine amidase, NAD ( P ) H dehydrogenase ( quinone ), superoxide dismutase, glutathione transferase, class 3 aldehyde dehydrogenase, glucose-6-phosphate isomerase, and tissue kallikrein ( function unknown ).

Not surprisingly, mice with Cu / Zn superoxide dismutase and FANCC mutations demonstrate defective haemopoiesis.

The superoxide is converted to hydrogen peroxide and singlet oxygen by an enzyme called superoxide dismutase.

However, Methanosarcina barkeri is exceptional in possessing a superoxide dismutase ( SOD ) enzyme, and may survive longer than the others.

However, in roundworms ( Caenorhabditis elegans ), blocking the production of the naturally occurring antioxidant superoxide dismutase has recently been shown to increase lifespan.

Although oxidative phosphorylation is a vital part of metabolism, it produces reactive oxygen species such as superoxide and hydrogen peroxide, which lead to propagation of free radicals, damaging cells and contributing to disease and, possibly, aging ( senescence ).

The reactive oxygen species produced in cells include hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), hypochlorous acid ( HClO ), and free radicals such as the hydroxyl radical (· OH ) and the superoxide anion ( O < sub > 2 </ sub >< sup >−</ sup >).

Superoxide dismutases ( SOD, ) are enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide.

Examples include superoxide, hydrogen peroxide, carbon monoxide, and hydrogen sulfide.

But the pKa of its conjugate acid, hydrogen superoxide ( HO < sub > 2 </ sub >·, also known as " hydroperoxyl " or " perhydroxy radical "), is 4. 88 so that at neutral pH 7 the vast majority of superoxide is in the anionic form, O < sub > 2 </ sub >< sup >−</ sup >.

One approach that has been used in quantitative assays, converts superoxide to hydrogen peroxide that is relatively stable.

In solutions at neutral pH, the superoxide ion disproportionates to molecular oxygen and hydrogen peroxide.

* A comparison of 7 non-primate mammals ( mouse, hamster, rat, guinea-pig, rabbit, pig and cow ) showed that the rate of mitochondrial superoxide and hydrogen peroxide production in heart and kidney were inversely correlated with maximum life span

Superoxide dismutates, spontaneously or through catalysis via enzymes known as superoxide dismutases ( Cu / ZnSOD and MnSOD ), to hydrogen peroxide, which is then converted to hypochlorous acid HClO, by the green heme enzyme myeloperoxidase.

Aqueous leaf extracts have been found to contain quinones such as the naphthoquinone plumbagin that couples to different NADH-dependent diaphorases to produce superoxide and hydrogen peroxide upon autoxidation.

MnSOD reduces superoxide to hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), but H < sub > 2 </ sub > O < sub > 2 </ sub > is not increased due to other cellular activity.

There are several ROS including: superoxide, hydrogen peroxide and hydroxyl, all of which lead to neurotoxicity.

* Toxic oxygen-derived products ( e. g., superoxide, hydrogen peroxide, hydroxy radicals, singlet oxygen, hypohalite )

Strictly speaking, the free radical theory is only concerned with free radicals such as superoxide ( O < sub > 2 </ sub >< sup >-</ sup > ), but it has since been expanded to encompass oxidative damage from other reactive oxygen species such as hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), or peroxynitrite ( OONO < sup >-</ sup >).

Superoxide then undergoes a further series of reactions to produce products such as hydrogen peroxide ( through the action of superoxide dismutase ), hydroxyl radical and hypochlorite ( bleach-through the action of myeloperoxidase on hydrogen peroxide ).

When a plant recognizes an attacking pathogen, one of the first induced reactions is to rapidly produce superoxide or hydrogen peroxide to strengthen the cell wall.

In particular, one major contributor to oxidative damage is hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), which is converted from superoxide that leaks from the mitochondria.

Superoxide dismutases ( SOD ) are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide.