Basics of Biology

Enzymes—and Proteins—at Work

Why is enzyme shape so important?

Obviously, it is difficult to track the activities of all the enzymes required by your body! However, in the case of the enzyme amylase, you can easily check to see if it is working. Amylase is an enzyme in your saliva that starts the breakdown of complex carbohydrates into simple sugars (glucose and maltose). A plain cracker held in the mouth long enough will begin this breakdown, and you will actually begin to taste the sweetness of the enzyme products. Also, lysozyme is an enzyme present in your respiratory tract secretions and tears. It prevents invasion by bacteria—which explains why the warm, moist, open environment of our eyes manages to remain relatively infection-free.

Shape is critical to the function of all molecules, but especially enzymes, which are three-dimensional. The “active site” of an enzyme is the area where the substrate binds and the reaction takes place. How an enzyme reacts with its substrate is similar to how a ship docks; minor bonds form between the enzyme and substrate until docking is complete. Thus, anything affecting a protein’s shape would have an effect on its “docking”— in other words, its ability to react with the substrate.


This is a web preview of the "The Handy Biology Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App