Enzymes: true multi-talents
What are enzymes?
Enzymes are proteins that are found in all organisms. They work as biocatalysts, which means that they “catalyze” or accelerate chemical processes without being altered themselves. Instead of waiting hours or even days for a reaction to occur spontaneously, enzymes can speed it up many times over, carrying out many reactions in less than a second. They are found in every cell of the body and are essential for all bodily functions. With regard to food intake, enzymes have the task of breaking down nutrients from food and thus making them more digestible. In this process, the first digestive enzymes already act as components of saliva in the mouth. Enzymes are also used in the production of food, for example in fermentation or baking, and more recently as potential candidates for environmental protection.
Our facts-to-go briefly and concisely summarized for you!
- Enzymes are proteins found in all organisms.
- Enzymes catalyze all reactions that take place in living organisms, and these reactions can be of various types, such as the production or breakdown of products of digestion.
- Most enzymes in the human body work best at about 37 °C — body temperature.
- Each of us produces different amounts of enzymes depending on our genes, diet, lifestyle, gender, age, or diseases such as Crohn’s disease, ulcerative colitis, and celiac disease.
- A deficiency in digestive enzymes can be associated with symptoms such as gas, bloating, heartburn and diarrhea.
- According to the German Federal Center for Nutrition, about 15% of Germans are lactose intolerant.
- Without enzymes, virtually nothing works in the production of food: they are present in almost all processed products.
- Pineapples, bananas, bean sprouts, papayas, mangoes, grapes, melons, apples, kiwis, avocados, ginger and sauerkraut are naturally rich in enzymes.
- Milk becomes lactose-free with the help of enzymes.
What does an enzyme look like?
Like any protein, enzymes are made up of amino acids. In nature, there are about 20 different types of amino acids. The different combination of amino acids used to build enzymes varies greatly from enzyme to enzyme and defines their properties. Some may consist of only 50 amino acids, others of more than 200, which is why there are millions of different proteins in nature, each with a specific amino acid sequence. But the most important thing is that the amino acid sequence of an enzyme determines its shape. And its shape determines its function.
How does biocatalysis work?
As we have already mentioned, the function of enzymes is to catalyze chemical reactions. A catalyst is a substance that increases the rate of a chemical reaction without being consumed by the reaction. Enzymes catalyze all reactions that take place in living organisms, and these reactions can be of various types, such as the formation or breakdown of products of digestion.
To better understand the process, let’s imagine a key and a lock. The reaction accelerated by the enzyme takes place inside the enzyme, also called the “active site” — for us it is the lock. The substance that is bound in the active site is the “substrate” — the key. The “substrate” interacts with the “active site” like the key interacts with the lock until the chemical changes have taken place. Only certain substrates “fit” into the active site. Once the reaction is complete, the product formed is released and the free enzyme can bind to a new substrate, starting the whole reaction over again.
Where do our enzymes come from?
The production of enzymes takes place — as with all proteins — according to protein building plans on the DNA. The building instructions are read and copied from the DNA and transported as so-called mRNA (messenger RNA) from the cell nucleus to the ribosomes, the site of protein formation. In the cell, enzymes normally have their fixed “place of action”, e.g. the enzymes of glycolysis in the cell plasma, the enzymes of the citrate cycle in the mitochondria, the enzymes of DNA formation and repair in the cell nucleus. Within the individual “compartments”, a distinction is made between those that are soluble, i.e. floating around freely, and those that are anchored, such as the enzymes of the respiratory chain localized in the mitochondrial membrane. There are also enzymes that are secreted by the cell to perform functions outside the cell. For example, digestive enzymes are secreted from cells of the stomach, pancreas, and gallbladder to break down nutrients in the food pulp.
Enzymes can work only under certain conditions. Most enzymes in the human body work best at about 37 °C — body temperature. At lower temperatures, they still work, but much more slowly. Similarly, enzymes can only work in a certain pH range (acidic/alkaline). Their preference depends on where in the body they are located. For example, enzymes in the intestines work best at a pH of 7.5, while enzymes in the stomach work best at a pH of 2 because the stomach is much more acidic. If the temperature is too high or the environment is too acidic or alkaline, the enzyme changes shape; this alters the shape of the active site so that substrates can no longer bind to it — the enzyme is functionless.
Examples of enzymes in our daily lives
As mentioned earlier, enzymes play a very important role by accelerating chemical reactions in our bodies, such as the breakdown of lactose.
But this is just one example of the millions of possibilities that exist. In addition to very technical applications, scientists have also used these biomolecules in industry to make all kinds of products. Today, they can be found in:
- Food
- Animal feed
- Cosmetic products
- Detergents
- flavors and fragrances
The best known examples are digestive enzymes. The human body produces 22 digestive enzymes, which are divided into three main groups: Proteases, Amylases and Lipases. Proteases help us break down dietary proteins, amylases digest carbohydrates, and lipases break down fats. But foods we ingest — especially those of plant origin — also contain their own enzymes that support our digestive enzymes. These include cellulases, for example, which break down what are actually indigestible dietary fibers and thus make them easier to digest.
Deficiency of digestive enzymes
Each of us produces different amounts of enzymes depending on our genes, diet, lifestyle, gender, age or diseases such as Crohn’s disease, ulcerative colitis and celiac disease. When these enzymes are all produced in the right amounts, digestion occurs properly, but what happens when we produce too few intestinal enzymes? As we age, the production of digestive enzymes decreases. A deficiency in digestive enzymes can be associated with symptoms such as gas, bloating, heartburn and diarrhea. You’ve probably heard of the enzyme lactase, which is deficient in lactose intolerance. According to the German Federal Center for Nutrition, about 15% of Germans are lactose intolerant. Lactase is naturally produced in the digestive tract, but as production decreases in adulthood, many adults are unable to effectively digest lactose. This can thus lead to lactose intolerance, in which the undigested lactose is fermented by intestinal bacteria and causes symptoms such as abdominal pain, diarrhea and flatulence.
Which foods are particularly rich in enzymes?
Without enzymes, food production would be virtually impossible: they are present in almost all processed products. Enzymes coagulate milk into cheese, loosen bread, or give cocoa and coffee beans their typical flavor. They are also used in textile and paper production, in environmental technology and as detergent additives. Around 80 percent of all enzymes used in the food industry are produced with the help of genetic engineering. Most enzymes are used as so-called technical adjuvants and therefore do not yet have to be approved or declared in the list of ingredients. Exceptions are enzymes that still have an effect in the end product, such as invertase contained in ice cream or chocolate, or lysozyme in cheese.
Naturally, pineapple, bananas, bean sprouts, papaya, mango, grapes, melons, apples, kiwis, avocados, ginger and sauerkraut are rich in enzymes. The bromelain in pineapple and the proteases in papaya are said to have various positive effects on health. They are said to have an anti-inflammatory, anticoagulant and digestive effect. Whether and to what extent their claimed effects occur is scientifically disputed. However, the enzymes in pineapple have not been proven to boost fat burning, as is often claimed.
Do dietary supplements with digestive enzymes help?
Digestive enzymes found in modern dietary supplements are mainly derived from fungi and bacteria. A dietary supplement with digestive enzymes can improve the digestion of fats, carbohydrates and proteins. Did you know that milk products become lactose-free with the help of enzymes? To make lactose-free milk, the enzyme lactase is added to normal milk to break down the milk sugar into glucose and galactose. Since these two simple sugars are sweeter than the two-sugar lactose, lactose-free milk tastes sweeter than conventional milk.
In addition, there have recently been dietary supplements that contain cellulase. Cellulase breaks down cellulose, a plant fiber found in all fruits and vegetables. Cellulose is the main component of plant cell walls and is extremely strong and tough. Humans cannot produce cellulase themselves and instead rely on the fermentation of cellulose by intestinal bacteria in the colon. Particularly with plant-based, high-fiber diets, cellulose is thought to aid in digestion and minimize common digestive symptoms such as bloating.
Why enzymes are the key to a sustainable future
There’s no denying that one of the biggest challenges facing the world today is the fight against climate change. It’s no wonder that in 2015, the UN came up with a list of sustainable development goals that specifically focus on climate-related issues and responsible production.
What many people don’t realize is that the use of enzymes on an industrial scale can make a big difference in the way companies operate, making a significant and positive impact on the environment. Why is that so? Some advantages of using enzymes are:
- Mild reaction conditions: Enzymes typically do not require harsh working conditions such as high temperatures or the use of solvents or other hazardous auxiliary chemicals.
- Environmental friendliness: enzymes can replace organic catalysts that otherwise require heavy metals and are released into the environment.
- Speed: enzymes are able to carry out chemical reactions extremely quickly
- Efficiency: under suitable reaction conditions, enzymes are able to process all available substrates and convert them into the desired product
- High product selectivity: enzymes are able to react with specific, targeted molecules, even in complex mixtures
- Savings: With the above advantages, companies can save resources.
In addition, and according to the OECD, the potential for mitigating climate change through biotechnology processes and biobased products (which include improved enzymes used in the chemical sector) is “between 1 billion and 2.5 billion tons of CO2 equivalent per year by 2030.”
Text Sources:
(2) Lehninger Principles of Biochemistry, 5th Edition. L Nelson and M.M Cox (2008)
(3) Neitzel, J. J. (2010) Enzyme Catalysis: The Serine Proteases . Nature Education 3(9):21
Image Sources:
(9) https://studyflix.de/biologie/enzyme-2662
(10) https://www.freepik.com/search?dates=any&format=search&page=1&query=milk&selection=1&sort=popular
