What are Enzymes?

Enzymes are proteins. Like other proteins, enzymes consist of long chains of amino acids held together by peptide bonds. They are present in all living cells, where they perform a vital function by controlling the metabolic processes whereby nutrients are converted into energy and fresh cell material. Furthermore, enzymes take part in the breakdown of food materials into simpler compounds. Some of the best known enzymes are those found in the digestive tract where pepsin, trypsin and peptidases break down proteins into amino acids, lipases split fats into glycerol and fatty acids, and amylases break down starch into simple sugars.

Enzymes are catalysts. Enzymes are capable of performing these tasks because, unlike food proteins such as case in egg albumin, gelatine or soya protein, they are catalysts. This means that by their mere presence, and without being consumed in the process, enzymes can speed up chemical processes that would otherwise run very slowly, if at all.

Enzymes are specific. Contrary to inorganic catalysts such as acids, bases, metals and metal oxides, enzymes are very specific. In other words, each enzyme can break down or synthesize one particular compound. In some cases, they limit their action to specific bonds in the compounds with which they react. Most proteases, for instance, can break down several types of protein, but in each protein molecule only certain bonds will be cleaved depending on which enzyme is used.

Enzymes are very efficient catalysts. For example, the enzyme catalyst, which is found abundantly in the liver and in the red blood cells, is so efficient that in one minute one enzyme molecule can catalyze the breakdown of five million molecules of hydrogen peroxide to water and oxygen.

Enzymes are part of a sustainable environment. Enzymes are present in all biological systems. They come from natural systems and when they are degraded, the amino acids of which they are made can be readily absorbed back into nature.

Enzymes work only on renewable raw materials. Fruit, cereals, milk, fats, meat, cotton, leather and wood are some typical candidates for enzymatic conversion in industry. Both the usable products and the waste of most enzymatic reactions are non-toxic and readily broken down..

Enzymes are at work in our bodies. Just eat something. One enzyme is already at work in your mouth while you chew; Amylases break down starch into smaller sugars - dextrins and maltose. Typical starchy foods are potatoes, pasta and rice. When the food reaches your stomach, acidic gastric juices start to flow from special glands. An important component of these juices is the enzyme pepsin. This is a protein splitting enzyme and it works best in the conditions of high acidity found in the stomach. The partly digested food and gastric juices are then churned around in your stomach and propelled into the duodenum. It is here that another important part of digestion takes place. Pancreatic juice is released from the pancreas and this neutralizes the acid. An enzyme contained in the juice chops starch into its simplest sugars, and another breaks the protein down further into amino acids, which are one of the main building blocks of all living matter. So far, any fat has remained untouched, but now an enzyme made in the pancreas, a lipase, digests the fat. About seven hours after you have eaten your food, it passes from the duodenum into the small intestine where most of the nutrients liberated by the enzymes are absorbed and pass into your blood. The work of the enzymes is over. They have performed a small miracle. They have helped to transform food into tiny nutrients that the body can absorb and use to renew aging cells and to provide energy. Each day muscles burn up several hundred grams of carbohydrate and fat for energy. Without enzymes, our bodies would cease to function.

Enzymes in Nature The biological carbon cycle in nature involves the uptake of carbon dioxide into plants, its fixation by photosynthesis, and the various ways in which it is returned to the atmosphere. Enzymes play an important role in all the biological processes of this cycle.

All our food, whether plant or animal, contains enzymes. All living organisms produce their own enzymes to provide the nutrients they need. Just as our bodies produce enzymes.