Protease is considered to be one of the most important enzymes that we have. If the digestive process is incomplete, undigested protein can wind up in your circulatory system, as well as in other parts of your body. Proteases help break proteins down into smaller proteins and amino acids. They can be of great benefit to people who have difficulty digesting proteins, but they have even broader therapeutic applications. Protease aids digestion of proteins and helps your immune system to fight infection.