Basics of Biology

Enzymes—and Proteins—at Work

How many enzymes are in the human body?

To date, approximately 75,000 enzymes are thought to exist in the human body—all divided into three classes: metabolic enzymes that run our bodies, digestive enzymes that digest our food, and food enzymes from raw foods that start our food digestion. A reason exists for so many enzymes: various metabolic functions may require a whole complex of enzymes to complete hundreds of reactions. In general, individual enzymes are named by adding the suffix “-ase” to the name of the substrate with which the enzyme reacts; for example, the enzyme amylase controls the breakdown of amylose (starch).


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