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).