Hydrogen peroxide has always been used to clean surfaces and remove tough stains and pathogens. You must have seen a brown bottle sitting around the corner of your house. This chemical is excellent to break down different substances.
However, did you know that there are certain substances that can break hydrogen peroxide too? Now you may know peroxide as a trusty chemical that helps you get rid of nasty stains and harmful bacteria. But this chemical is not so favorable when it’s inside your body!
Peroxide is a free radical that causes multiple problems if left alone inside your system. For that reason, your body contains an enzyme called catalase that’s responsible for breaking down hydrogen peroxide to prevent oxidative stress.
So, read on as we tell you all about catalase-mediated hydrogen peroxide breakdown; how it happens and why is it important.
What Is Catalase?
Catalase is an antioxidant enzyme that protects the body against toxins and harmful substances. It is commonly found in nearly all aerobic organisms. In mammals, it is mainly found in the liver.
The enzyme plays a vital role in protecting the cell and its organelles from oxidative damage by the reactive oxygen species. Catalase is a ubiquitous enzyme that brings about the decomposition of hydrogen peroxide, which is continuously produced by various metabolic reactions in the body, into water and oxygen.
The reaction takes place in an energy-efficient manner in the cells that are exposed to environmental stress.
The optimum pH at which human catalase works best is approximately 7. The optimum temperature varies between different species.
Catalase is a tetrameric enzyme consisting of four polypeptide chains. Each chain is over 500 amino acids long. Four iron-containing heme groups in the center of each chain allow the enzyme to react with hydrogen peroxide.
The enzyme has several industrial applications. In the food industry, it is combined with other enzymes to preserve foodstuffs and manufacture beverages and certain food items. Commercial catalases play a significant role in breaking down hydrogen peroxide in wastewater.
Can Catalase Break Down Hydrogen Peroxide
Catalase can break down hydrogen peroxide with ease. In fact, the enzyme’s sole purpose in the human body is to metabolize hydrogen peroxide and turn it into harmless substances.
It is found in the liver to break down harmful and poisonous hydrogen peroxide into harmless substances— a neutral water molecule and oxygen gas. The oxygen gas that is formed as a result of this reaction escapes and creates foam.
How Is Hydrogen Peroxide Broken Down By Catalase?
The mechanism via which catalase breaks down hydrogen peroxide is twofold. Firstly, the enzyme lowers the activation energy of the reaction by allowing peroxide to make a high-energy intermediate, which we call the peroxide-catalase complex.
Subsequently, this complex converts into the oxygen-water-catalase complex via the action of the enzyme. At the molecular level, catalase cleaves the bond present between the two oxygen atoms to release them.
Soon after, this second complex is also broken down. This time, we get the final products; water and oxygen. It is important to note that the enzyme is also regenerated in this process and is ready to take on the next peroxide molecule.
How Much Hydrogen Peroxide Can Catalase Break Down?
The enzyme catalase is exceptionally efficient. The rate of decomposition of hydrogen peroxide by catalase is immensely high, with the substrate turnover number being more significant than that of any other enzymatic reaction.
One catalase molecule can dismutate over 40 million molecules of hydrogen peroxide into water and oxygen per second; therefore, it has the highest turnover numbers of all enzymes. The enzyme is extremely important for survival as it prevents the accumulation of hydrogen peroxide to dangerous levels.
Can Hydrogen Peroxide Decompose Without Catalase?
Hydrogen peroxide is a reactive oxygen species that can decompose naturally into water and oxygen without the need for the enzyme catalase.
The chemical structure of hydrogen peroxide explains why hydrogen peroxide can decompose very quickly. It consists of a single oxygen–oxygen bond. Also known as the peroxide bond, the bond is fragile and unstable.
When the oxygen-oxygen bond is broken, hydrogen peroxide is decomposed, releasing free radicals that are highly reactive.
While the catalase enzyme can act as a catalyst to speed up the decomposition reaction of hydrogen peroxide, the instability of the peroxide bond makes it easier for decomposition to occur naturally.
Where Is Catalase Found?
Catalase is found in nearly all living organisms exposed to oxygen, like plants, animals, and bacteria. In mammals, it is located predominantly in the liver, where various metabolic reactions produce hydrogen peroxide and other toxins that need to be removed.
At the cellular level, catalase is found in all major sites where hydrogen peroxide is produced, such as peroxisomes, mitochondria, and cytosol. It is also present in the chloroplast in higher plants.
Commercial Use of Catalase to Break Down Hydrogen Peroxide
Technological advancements have made it possible for us to recreate different bodily reactions and implement them at a larger scale. Over the past few years, commercial production and usage of catalase have begun and there are two main spots where we’re seeing this.
Waste Water Treatment
Sewage has an array of microbes present in it that decompose organic waste and produce harmful compounds. These products are not just harmful to the environment but they also damage the piping and storage from where the waste flows.
This is a big concern as we cannot afford to lose the piping. For that reason, catalase is used at a massive scale to treat this water. The most potent oxidizing agent in this water is hydrogen peroxide, and as you guessed, catalase gets rid of it.
Another application of this enzyme in the same domain is when wastewater is being converted to usable water. Catalase removes peroxide from the water to make the water usable and less harmful.
Production of Food Preservatives
The same principle applies here as well. When packing food, you need to ensure that there are no compounds present in the packaging that make the food go rancid. Oxygen is your biggest enemy when it comes to preserving food.
You see, food goes bad when bacteria get oxygen and thrive. That’s why food packets are either vacuum sealed or filled with nitrogen gas. Catalase helps remove peroxide from the mix to ensure that no oxygen is produced later when the pack is closed.
The Importance of Catalase-Mediated Hydrogen Peroxide Breakdown
Getting rid of hydrogen peroxide is essential as it can cause several issues at the cellular level. For starters, peroxide causes an oxidative burst that can harm cell organelles, ultimately leading to cell death and necrosis.
Moreover, high levels of peroxide are also harmful as they react with different metabolic products present in the blood. Perhaps the best example of this dilemma is peroxide reacting with fatty acids. The molecule oxidizes the free fatty acids, causing them to deposit on the vessel walls.
For those who don’t know, this is exactly how heart and vascular problems develop. Therefore, catalase is a life-saving enzyme that deals with these chemicals and keeps its levels within a narrow range.
Here are two of the most notable features of catalase-mediated hydrogen peroxide breakdown:
#1 Removal of Toxins
There are certain species present inside your body that can kill the cells within seconds. Many of them are derivatives of oxygen, and for that reason, this class of compounds is called Reactive Oxygen Species or ROS.
Hydrogen peroxide is a prominent ROS and it can damage the mitochondrial membrane, leading to cellular apoptosis. The body, however, deals with these ROS by producing antioxidants.
Catalase is a potent antioxidant that not just breaks down peroxide but also ensures that no free substrate is present for other enzymes to shunt and produce other free radicals. The products are plain old water and oxygen so that no side reactions occur.
#2 Oxidative Burst to Kill Pathogens
After discussing all these negative effects of peroxide and the need to remove it in an attempt to prevent damage, here’s something out of the blue!
Your body also makes use of peroxide to kill unwanted invaders. In particular, cells of your immune system work in this manner. Neutrophils make the first line of defense against pathogens trying to enter your system.
Their mechanism of action is entirely dependent on the catalase-mediated peroxide breakdown. Catalase breaks down the peroxide into a free radical derived from oxygen. This superoxide radical is then converted to hypochlorous acid by the enzyme myeloperoxidase.
The final product is a lethal substance that kills pretty much all bacteria and most fungi. Catalase plays a pivotal role in this procedure by providing the substrate as well as controlling the rate of reaction.
The Takeaway
Enzymes are natural catalysts that make your bodily reactions happen at a faster rate. Without essential enzymes, we couldn’t even last a few minutes. Catalase is one such enzyme, and you’ve seen how crucial it is in helping your body fend off pathogens and ROS.
You’ve seen how catalase breaks down hydrogen peroxide and where and why it works as it does. Like every enzyme, catalase also needs a proper environment to function effectively. Besides, we’ve seen the use of catalase commercially to treat wastewater and make preservatives for the food industry.
You can also try the effect of catalase on hydrogen peroxide as a fun experiment for you and your kids. So, order your set of hydrogen peroxide bottles today!
