What Are Enzymes? What They Do and Why the Body Needs Them

What Is an Enzyme?

An enzyme is a tiny structure that helps the body complete a particular job.

For example, some enzymes help break food into pieces small enough for the body to use. Other enzymes help cells produce energy, repair damage, remove waste, or copy genetic instructions when new cells are made.

Each enzyme has a particular shape. That shape allows it to work with certain materials, much like the correct tool fits a particular part.

Scientists describe enzymes as biological catalysts:

• Biological means connected to living things.
• A catalyst helps something happen faster.

Together, these words mean that an enzyme helps a change happen fast enough for the body to use it.

Scientists call that change a chemical reaction. Despite the intimidating name, chemical reactions happen throughout ordinary life. Cooking an egg, burning fuel, digesting food, and producing energy inside a cell all involve materials being changed into something else.

What Do Enzymes Do in the Body?

Enzymes perform thousands of different jobs. Some familiar examples include:

• Digesting food: Enzymes break carbohydrates, fats and proteins into smaller pieces the body can absorb and use.
• Producing energy: Enzymes help cells turn nutrients into usable energy.
• Repairing and building: Enzymes help the body build new materials and repair damaged cells.
• Copying genetic instructions: Enzymes help copy DNA when cells divide. DNA contains the instructions cells use to operate.
• Removing unwanted substances: Enzymes help the liver and other organs process substances the body needs to remove.
• Clotting blood: Enzymes participate in the chain of events that helps stop bleeding after an injury.
• Controlling signals: Enzymes help start, stop or adjust some of the messages used by cells.

Digestive enzymes receive considerable attention because their work is easy to connect with eating. They are only one part of a much larger system. Enzymes help make nearly every body process possible.

How Do Enzymes Work?

An enzyme works by temporarily connecting with the material it is designed to change.

Imagine a pair of scissors cutting paper. The scissors help make the cut, but they do not become part of the paper. After one cut, they can be used again.

An enzyme works somewhat like that:

1. The correct material reaches the enzyme.
2. It fits into a particular area on the enzyme.
3. The enzyme helps change the material.
4. The changed material is released.
5. The enzyme can usually perform the job again.

Scientists call the material an enzyme works on a substrate. The area where the substrate connects with the enzyme is called the active site.

The enzyme's shape matters because the substrate must fit closely enough for the enzyme to do its job. This is why one enzyme cannot perform every job in the body.

Depending on its purpose, an enzyme may help:

• Break one material into smaller pieces
• Join smaller pieces together
• Rearrange part of a material
• Add or remove a small component
• Transfer something from one material to another

An enzyme does not decide what the body needs or create energy by itself. It makes a particular step easier and faster to complete.

Are Enzymes Proteins?

Most enzymes are proteins, but not every protein is an enzyme.

A protein is a tiny working structure made from smaller pieces called amino acids. The amino acids connect and fold into a particular shape. That shape helps determine the protein's job.

Some proteins provide structure. Others carry materials, receive signals, help the immune system, or allow muscles to move. Proteins that help chemical changes happen faster are called enzymes.

A simple way to remember the difference is:

• Protein describes what the structure is made from.
• Enzyme describes the job that certain proteins perform.

A hammer is a tool, but not every tool is a hammer. In the same way, most enzymes are proteins, but most proteins perform other jobs.

There is one unusual exception. A small number of RNA structures can also help chemical changes happen. Scientists call these ribozymes. Their existence is why the accurate statement is “most enzymes are proteins” rather than “all enzymes are proteins.”

Do Enzymes Get Used Up?

An enzyme can usually perform the same job repeatedly.

Cutting one piece of paper does not normally destroy the scissors. In a similar way, an enzyme helps complete a change without becoming part of the finished result. After releasing the changed material, it can often repeat the process.

That does not mean enzymes last forever. The body continually makes, regulates, and breaks down enzymes. An enzyme may also stop working properly if its shape is damaged or the conditions around it change too much.

Some substances can slow or block an enzyme. Scientists call these substances enzyme inhibitors. Other substances may help an enzyme work. The body uses both kinds of control to adjust when particular jobs happen and how quickly they proceed.

Why Do Shape, Temperature, and Acidity Matter?

An enzyme's shape helps it perform its job. If that shape changes too much, the correct material may no longer fit.

Cold conditions generally slow many enzyme-controlled processes. Excessive heat can damage an enzyme's structure and prevent it from working properly.

Acidity also matters. Scientists measure acidity using pH. Different parts of the body have different pH conditions.

For example, the stomach is highly acidic. Enzymes that work in the stomach are suited to that environment. Other enzymes work better in the less acidic conditions found elsewhere in the digestive system or inside cells.

Each enzyme has a range of conditions in which it works effectively. Moving too far outside that range may slow the enzyme or change its shape enough to stop the job.

Illness and inherited genetic changes can also affect enzymes. In some conditions, the body:

• Does not make enough of a needed enzyme
• Produces an enzyme with the wrong shape
• Cannot move the enzyme to the place where it is needed
• Cannot regulate the enzyme correctly

What happens next depends on the enzyme and the job it normally performs.

Digestive Enzymes Are Only One Category

Digestive enzymes help break food into pieces small enough for the body to absorb and use.

Three familiar categories are:

• Amylase: Helps break carbohydrates and starches into smaller sugars.
• Protease: Helps break proteins into amino acids and smaller protein pieces.
• Lipase: Helps break fats into smaller components the body can absorb.

Another example is lactase, which helps break down lactose, the natural sugar in milk. When the body does not make enough lactase, lactose may pass through the digestive system without being fully broken down. This can cause gas, bloating, pain, or diarrhea in people with lactose intolerance.

The body makes digestive enzymes in several places, including the mouth, stomach, pancreas, and small intestine.

Digestive-enzyme supplements are also sold to consumers, but a supplement is not automatically necessary or appropriate simply because enzymes are essential to the body. The reason for taking a product, the enzyme it contains, its strength, and a person's medical needs all matter.

Prescription pancreatic-enzyme products are different from general supplements. They may be prescribed when the pancreas cannot release enough enzymes to digest food properly. That is a specific medical use requiring professional evaluation.

Can Enzymes Be Medicines?

Yes. Some enzymes are used as medicines.

If a medical condition leaves the body without enough of a particular working enzyme, a manufactured version may sometimes replace part of the missing function. This is called enzyme replacement therapy.

These treatments are not general enzyme boosters. Each one is developed for a particular enzyme problem and medical condition.

Some enzyme medicines are made using genetically engineered cells. The cells are given instructions that allow them to produce a version of a human enzyme. The enzyme is then collected, purified, tested, and prepared as a regulated medical product.

Scientists often call this a recombinant enzyme. In ordinary language, that means an enzyme produced with the help of genetically engineered living cells. The FDA has approved specific recombinant enzyme-replacement products for certain diseases.

Depending on the treatment, an enzyme medicine may be swallowed, inhaled, injected, or administered through a needle placed into a vein. Medicine delivered directly into a vein is called an intravenous infusion.

FDA approval applies to a particular product, condition, patient population, dose, and method of use. It does not mean that every product carrying an enzyme's name is approved, properly manufactured, or appropriate for human use.

Enzyme medicines can also cause serious side effects. Because enzymes are proteins, the immune system may react to them. Certain intravenous enzyme-replacement therapies carry risks of severe allergic reactions and require medical monitoring.

A supplement, a laboratory research material, and an FDA-approved enzyme medicine are not interchangeable. Their manufacturing standards, testing, intended uses, and medical oversight can be very different.

Enzymes, Proteins, Peptides, and Hormones

These terms overlap, but they do not mean the same thing.

Protein

A protein is a structure made from connected amino acids. Proteins can provide support, carry materials, receive signals, defend against threats, or perform many other jobs.

Enzyme

An enzyme helps a particular change happen faster. Most enzymes are proteins, but “enzyme” describes the job rather than simply what the structure is made from.

Peptide

A peptide is also made from connected amino acids, but it is generally smaller than a protein. Some peptides work as signals that tell cells or organs what to do.

Hormone

A hormone is a chemical messenger. It is made in one part of the body and carries instructions to another part.

Some hormones are proteins or peptides. Others are made from different materials, such as cholesterol. “Hormone” describes the signaling job the substance performs.

A molecule may fit more than one category. For example, a protein can also be an enzyme, and a peptide can also act as a hormone. The categories describe different aspects of what something is made from or what it does.

The Simple Takeaway

Enzymes help the body complete essential jobs quickly enough to sustain life.

Most enzymes are proteins shaped for particular tasks. They help digest food, produce energy, repair cells, copy genetic instructions, remove waste, clot blood, and control many other processes.

Digestive enzymes are only one group. Enzymes work throughout the body, and some regulated medicines can replace a particular enzyme that is missing or not functioning properly.

Understanding enzymes also makes proteins, peptides, hormones, digestion, metabolism, and certain medicines easier to understand. In the simplest terms, enzymes are specialized helpers that keep the body's work moving.