The cells of all living organisms contain special proteins called enzymes. These enzymes function as catalysts in that they speed up chemical reactions in cells. Digestive, metabolic, and food enzymes are the major types in the human body. Without these enzymes, the human body would not be able to function properly.
Enzymes, as proteins, are made up of strands of amino acids. Each enzyme has a special region called an active site. The active site has a specific shape that fits with certain molecules called substrates or reactants. The substrates are attracted to the particular enzymes for which they are matched and will attach themselves to those enzymes, like a puzzle piece fitting into its proper slot.
When the enzymes bind with the substrates, they form what is called an enzyme-substrate complex. The enzymes function to alter the chemical bonds in the substrates, causing the substrates to form a new bond. The new bond that is formed results in the production of an entirely different molecule. The new molecules that are formed are called products. The process of converting substrates to products is called catalysis.
After the enzymes function to create products, they return to their original shapes. They are not altered in the process and are then free to act as catalysts again for a new set of substrates. Sometimes, two or more substrates can bond together to form one product. In other instances, particular enzymes function to create two products from a single substrate.
Three main enzyme groups take care of these processes in the human body, including digestive, metabolic, and food enzymes. Digestive enzymes, secreted mainly along the digestive tract, function to break down food and convert it to energy. Metabolic enzymes are responsible for cellular reactions related to energy production and detoxification. Both enzymes are produced by the cells in the body and are necessary for its proper function.
Food enzymes are those that are found in most raw foods and animal products that people consume. It is questionable whether food enzymes function as catalysts in the body after they are consumed. This is because enzymes found in raw foods, when eaten, are simply digested just like any other protein. In other words, enzymes consumed in that manner do not live on in the body to carry on the job of a catalyst. Some groups of individuals, particularly companies that market enzyme supplements, believe that food enzymes, when consumed, do aid in proper digestion and breakdown of certain types of foods.