Enzymes are produced by living cells and are capable of speeding up chemical reactions. Highly efficient, specific, specialized and catalytic, enzymes are essentially composed of proteins or small amounts of RNA. Enzymes catalyze reactions by reducing the activation energy required for the reaction. Enzymes can be classified according to their mechanism of action as transferase, hydrolase, cleaving enzyme, oxidoreductase, and so on. Enzymes are catalysts of human metabolism and participate in the formation and decomposition of a variety of substances, such as hexokinase, 3-phosphoglyceraldehyde dehydrogenase and other enzymes to participate in the metabolic utilization of glucose, lipase to promote the decomposition of fats and so on. If the lack of a certain enzyme, can interfere with the normal physiological process, resulting in the occurrence of certain diseases, such as the lack of tyrosinase, can cause albinism, such as the lack of pepsin, can cause indigestion. If the body once the lack of enzyme, will appear corresponding symptoms, should promptly seek medical attention, under the guidance of the doctor for targeted treatment, so as not to delay the condition.