Proteins have lots of important functions in the body. One of them is to work as biological catalysts, which means they cause chemical changes or reactions in other substances. This group of proteins, called enzymes, bring about changes in the body while they remain unchanged themselves during the process. Learning the origins of the word “enzyme” may make it easier to understand how enzymes work.

People unknowingly used enzymes for centuries when they were baking bread, making cheese or fermenting sugars into alcohol. The term “enzyme” comes from the Greek word “enzumos,” which means “leavened.” During bread making, an enzyme called amylase breaks down a complex carbohydrate starch into smaller molecules (sugars) that are eaten by yeast in a dough. As yeast digests these sugars (also by using enzymes), bubbles of carbon dioxide released create tiny holes in the bread. The enzymes are the catalyst for making the bread lighter and fluffier.

We also have amylase in our saliva. It allows us to begin digesting carbs such as potatoes and bread while it’s in our mouth. In our stomach, another enzyme called pepsin breaks down proteins into peptides. In the next region of our digestive tract, another enzyme, called trypsin, breaks down proteins.

The names of enzymes often provide helpful information about their function. For example, pepsin and trypsin are called proteases: “prote” for protein and “ase” for enzyme. An enzyme that breaks down lipids (fats) is called lipase.

Each enzyme requires specific conditions, such as just the right temperature and acidity level, to do its job properly. While our body maintains a temperature within tight limits, acidity requirements vary depending on the organ where the enzyme functions. Pepsin, for example, needs stomach acid to activate and do its job. This acidic environment, however, will damage liver or pancreatic enzymes.

While we mainly hear about enzymes in relation to digestion, it is important to note that enzymes help increase the speed of all chemical reactions throughout our body, whether they act to break down molecules or build new ones. Many life-threatening diseases are associated with the absence or loss of function of specific enzymes. The bottom line: Enzymes are crucial for our continued good health.

Natalya Zinkevich, PhD, is an assistant professor at the University of Illinois at Springfield. She teaches courses related to human anatomy and physiology, health and disease, and vertebrate zoology. Her research primarily focuses on the cardiovascular system.