There are many different types of enzymes, okay, thousands of enzymes. Each enzyme has a particular function. When enzymes are at their optimum temperature and pH, they can build something up, that is to say, synthesize it. These are the metabolic enzymes. Digestive enzymes will break larger molecules down into something the body can use. Some enzymes come directly from the foods we eat. With so many different types of enzymes, how does our body know how to use them?