Is Catalase An Enzyme? 9 Facts You Should Know

Catalase is an enzyme that decomposes hydrogen peroxide into simpler forms, oxygen and water to protects the cells from oxidative damages.

Enzymes are the proteins in the body that engage in speeding up the metabolism rate and ensure facilitating various chemical reactions in the body. Catalase is one such enzyme in all the living organisms which is produced naturally within the body to support daily activities. 

Why is catalase an enzyme?

Catalase is termed as an enzyme because it is an important protein present in almost all living organisms to support the important chemical reaction in the body.

Catalase works to decompose hydrogen peroxide into simpler forms, oxygen and water. It is important for the body as it protects the cells from oxidative damages that can be caused by the Reactive Oxygen Species (ROS). 

How is catalase an enzyme?

Catalase enzyme supports the chemical reaction in the body by binding to the substrate hydrogen peroxide.

Every enzyme has its specific substrate to which it goes and binds, and for catalase, its substrate is hydrogen peroxide, which is a nonradical ROS. The catalytic property of catalase enzymes is to establish neutralisation by decomposing hydrogen peroxide into hydrogen and water. 

The decomposition of hydrogen peroxide helps in maintaining an optimum level of molecule with the cells, which is further helpful in facilitating the cellular signalling processes. 

What group of enzymes is catalase?

The enzyme catalase, which is also known as peroxidase, is identified to fall under the oxidoreductase class of enzymes. This enzyme facilitates the decomposition of hydrogen peroxide into water and hydrogen. 

Where is catalase enzyme found?

Catalase is found in all the living beings in the major sites where hydrogen peroxide is produced.

Catalase is found in almost all living beings, starting from bacteria, plants and animals. In the cellular environment, catalase is found in all the major sites where hydrogen peroxide is produced like peroxisomes, cytosol, chloroplast and mitochondria. 

In the mammals, catalase is mostly found in the liver organ as it has the highest accumulation of peroxide. On a cellular level, it is found mostly in the peroxisomes of the mammalian cells. Catalase helps in the prevention of the excess accumulation of hydrogen peroxide to protect the organs and tissues from damage. 

Functions of catalase enzymes

Few of the functions that catalase enzymes have within the body are as follows: 

Cellular Role

Catalase enzyme is utilised in the body by the cells in catalysing the reaction of decomposing hydrogen peroxide into substances that are less reactive forms like the gaseous oxygen and water molecules. It protects the cells from oxidative damages that can be caused by the Reactive Oxygen Species (ROS).  

The daily metabolic processes within our body produces the harmful byproduct hydrogen peroxide which needs to be removed in order to prevent any form of damage to the cells, tissues or even organs. The hydrogen peroxide byproducts need to be converted in the less dangerous forms within the body.  

Peroxisomes within the plant cells engage in the process known as photorespiration where there is a utilisation of oxygen in producing carbon dioxide as well as symbiotic nitrogen fixation. Hydrogen peroxide is utilised as a potent antimicrobial agent during the times the cells are infected by various pathogens within plants. 

Catalase-positive pathogens, which can be the Mycobacterium tuberculosis, Legionella pneumophila and Campylobacter jejuni have the ability to deactivate the peroxide radicals which can lead to the survival of these pathogens in the host as the catalase remain unable to identify them. 

Structure of catalase enzymes

Catalase is a decomposing enzyme which is tetrameric in nature and has four identical and tetrahedrally arranged subunits. Each of the subunits are 60kDa and each one has an active centre which contains a heme group as well as NADPH. In catalase, the monomers wrap around each other to provide a dumbbell shape to the enzyme. 

is catalase an enzyme
Catalase Enzyme from Wikimedia

Can catalase be a substrate?

Catalase cannot be a substrate as it is an enzyme.

Catalase is an enzyme that engages in accelerating a reaction within the body. Catalase works on a substance, which is called the substrate and for catalase, the substrate is hydrogen peroxide. 

Catalase works on the substrate hydrogen peroxide to facilitate the decomposition process to form water and oxygen. If the reaction is not facilitated by the body, it might damage the body organs. Thus, Catalase helps in the prevention of the excess accumulation of hydrogen peroxide to protect the organs and tissues from damage.

Is catalase enzyme a protein?

All enzymes are protein, hence catalase is also a protein.

Catalase is a form of protein, infact, all the enzymes are proteins. Catalase is identified as a tetramer which is made up of four polypeptide chains. Each of the chains are 500 amino acids long and contain a heme group in order to facilitate the reaction with hydrogen peroxide. 


In conclusion to “is catalase an enzyme” in the article, it can be identified that Catalase is an important enzyme present within all living organisms and helps in decomposing hydrogen peroxide to hydrogen and water to protect the organs from damage due to peroxide.

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