An agent that performs many crucial functions in the body. The body has thousands of different proteins, each of which has its own specialized function; that function is determined by its structure and shape.

All enzymes are proteins, but not all proteins are enzymes. There are three types of proteins: Enzymes, which are catalysts that create and speed up biochemical reactions; structural elements, or the main material of our bones, muscles, hair, skin, and blood vessels; and antibodies, protectors that recognize invading elements and allow the immune system to get rid of these invaders.