Enzymes are special types of proteins and are made from amino acids. Enzymes help to produce and speed up chemical reactions inside the body when the body needs to get things accomplished.

Enzymes work with certain substances that are specifically made for them. This means that one enzyme will not do the work of an enzyme that is supposed to be doing something different.

What Does an Enzyme Do?

Enzymes have active sites, which are a place on the surface that fits the molecule that it is reacting with in to.

The active site is like a pocket and the molecule fits perfectly there. The molecule that the enzyme is reacting with is called a substrate.

When the substrate is at the active site, a reaction takes place and then a new substance is released by the enzyme called a product.

The product that leaves the site of the enzyme is different than the product that started in the enzyme.

What Can Make Enzymes Work Differently?

Different things can change the way that the enzyme and substrate react. The environment, for example, can change the speed of the reaction and it can cause the enzyme to even stop working.

When an enzyme stops working, this is called denatured. The temperature can change the way that an enzyme and substrate react.

If the temperature is higher, it can cause the reaction to happen faster. If the reaction continues to speed up, it will cause the enzyme to denature, or to stop working.

The pH level in the environment or how much acid is in the environment, can cause the enzyme and the substrate to react differently.

If the pH is too high, it will cause the reaction to slow down. If the pH is too low, it will also cause the reaction to slow down. When this happens, the reaction will eventually stop.

Having too much of an enzyme or a substrate can cause the reaction rate to speed up.


There are certain molecules that are used to stop enzymes and substrate activity, and these are called inhibitors.

These inhibitors can either slow down the reaction or even stop it. Some of the inhibitors stick to the enzyme and cause it to lose its original shape and stop it from working correctly.


An activator is the opposite of an inhibitor. The activator will change the way that the enzyme and the substrate react. An activator always speeds up the reaction of the enzyme.

Facts About Enzymes

  • Enzymes are used over and over and are not released from the body.
  • Drugs act as inhibitors, slowing down the process of the enzyme.
  • Enzymes are in your saliva and they are called amylase.
  • Amylase are enzymes in the saliva that help break down food.
  • Enzymes break down our food and are found in different parts of the body such as the pancreas, saliva, stomach, small and large intestine and more.

What Did You Learn?

  • What are enzymes made of? Enzymes are made up of amino acids.
  • What does it mean that an enzyme is specific? An enzyme is specific because each enzyme does a specific job and does not try to do another enzymes job.
  • What is the part of the enzyme called that is like a pocket? The pocket like area on the enzyme is called the active site.
  • What does the enzyme react with? The enzyme reacts with the substance, substrate.
  • When the enzyme and the substrate complete their task, what do they make? When the enzyme and substrate complete their task, they make the product.
  • How does the environment affect the enzyme? The environment can speed up or lower the reaction of the enzyme and the substrate.