Medical Genetics Simply put, enzymes help the body by stimulating biological reactions inside cells. Enzymes are proteins that help the body use food, produce energy, and do work. When a particular enzyme is defective or missing, then the body isn't able to do something that it should do to maintain health. The enzyme involved determines what the body can't do and what the resulting physical features areMedical Genetics Simply put, enzymes help the body by stimulating biological reactions inside cells. Enzymes are proteins that help the body use food, produce energy, and do work. When a particular enzyme is defective or missing, then the body isn't able to do something that it should do to maintain health. The enzyme involved determines what the body can't do and what the resulting physical features are