Life as we know it wouldn’t exist without enzymes. These tiny proteins, found in every living organism, are the catalysts that make nearly all the chemical reactions in our bodies possible. Without them even the simplest tasks, like digesting food or healing a wound, would take an impossibly long time to complete.

So, what exactly are enzymes and why are they so important?

Enzymes are biological molecules, primarily proteins, that speed up chemical reactions. In chemistry a catalyst is something that increases the rate of a reaction without being consumed or altered in the process. That’s what enzymes do — they help reactions happen faster and more efficiently without being used up themselves.

Without enzymes many of the chemical reactions necessary for life would proceed too slowly to sustain an organism. Think of enzymes like assembly line workers in a factory, speeding up the process and ensuring that each task happens at just the right time.

Enzymes work by lowering what’s called the “activation energy” of a reaction. Activation energy is the amount of energy needed to get a reaction started. By lowering this barrier, enzymes allow reactions to happen much faster than they would on their own.

Each enzyme is specific to one or a few particular reactions. This specificity comes from the enzyme’s shape. Most enzymes have an area called the “active site,” where a molecule called the substrate binds. Think of it like a lock and key: The enzyme is the lock and the substrate is the key. When the key fits into the lock, the reaction can proceed. The enzyme then helps convert the substrate into new products.

For example, when you eat a meal, enzymes in your saliva and digestive system break down the food into smaller molecules that your body can absorb and use for energy. Amylase, an enzyme in saliva, starts breaking down starches into sugars before they even reach your stomach.

Enzymes are responsible for countless essential processes in the body. They play a role in digestion, energy production, DNA replication and even the detoxification of harmful substances. Some well-known enzymes include:

>> Amylase: Breaks down starches into sugars.

>> Lactase: Helps digest lactose, the sugar found in milk.

>> DNA polymerase: Plays a critical role in copying DNA during cell division.

Each of these enzymes is highly specialized, working only on specific molecules under specific conditions. Temperature, pH levels and even the concentration of substrates can affect how well an enzyme performs.

Sometimes, enzymes can be blocked by other molecules called inhibitors. These inhibitors prevent the enzyme from doing its job, slowing down or stopping the reaction. Enzyme inhibitors can naturally occur or be introduced through medications. Many drugs work by inhibiting enzymes. For example, some pain relievers block enzymes involved in producing inflammation, helping to reduce pain and swelling.

Enzymes are fundamental to life because they ensure that our body’s complex chemical processes happen quickly and efficiently. Without enzymes these processes would take far too long to sustain life. Whether you’re digesting food, repairing cells or simply breathing, enzymes are working behind the scenes to keep everything running smoothly.

So, the next time you sit down for a meal, take a moment to appreciate the unsung heroes — enzymes — that help turn that food into the energy your body needs to thrive.

Richard Brill is a retired professor of science at Honolulu Community College. His column runs on the first and third Fridays of the month. Email questions and comments to brill@hawaii.edu.