Although most enzymes are proteins, some must be attached to certain nonprotein molecules in order to function. Many of these nonprotein molecules are metals, such as copper, iron, or magnesium. Others are organic compounds called coenzymes. If a coenzyme is tightly attached to the protein part of the enzyme, the unit is called a prosthetic group. Neither the coenzyme nor the protein part of a prosthetic group can function alone.
Many coenzymes consist of vitamins, especially B vitamins.
If a person's diet lacks adequate amounts of these vitamins, the enzymes cannot function properly, and various body disorders may develop. See Vitamin . Enzymes have many uses in addition to their natural functions in the body. Manufacturers use enzymes in making a wide variety of products. For example, some detergents contain enzymes that break down protein or fats that cause stains.