Enzymes are protein molecules that act as catalysts in chemical reactions within living organisms. Without them, most of these reactions would be too slow to support life. Enzymes are, in a sense, the "keys" that unlock the doors to chemical life in our bodies.<br /><br />Chemical Structure of Enzymes:<br /><br />Most enzymes are proteins made up of long chains of amino acids, folded in a special way to form an active site that interacts with the target substance (substrate). Some enzymes require cofactors, such as metal ions or small organic compounds (called coenzymes or "coenzymes").<br /><br />Mechanism of Enzyme Action:<br /><br />Enzymes work via what is known as a "lock-and-key model," where the enzyme binds to the substrate in a very specific way, and the key opens the appropriate lock. After the reaction is catalyzed, the enzyme releases the product and returns to its original state to repeat the process.<br /><br />Factors affecting enzyme function:<br />1. Temperature: Each enzyme has an optimal temperature, often around 37°C (body temperature).<br />2. pH: This varies from enzyme to enzyme; for example, the stomach enzyme pepsin works in an acidic medium.<br />3. Substrate concentration: Increasing the substrate speeds up the reaction until the enzyme reaches saturation.<br />4. Presence of inhibitors: Some substances temporarily or permanently inhibit enzyme function.<br /><br />Examples of well-known enzymes:<br />• Amylase: breaks down starches in the mouth.<br />• Lipase: breaks down fats.<br />• Pepsin: digests proteins in the stomach.<br />• DNA polymerase: aids in DNA replication.<br /><br />Importance of enzymes in life and applications:<br />• Digestion: facilitates the breakdown of food into simple components.<br />• Medicine: used in the manufacture of drugs and treatments.<br />• Industry: used in the manufacture of cheese, bread, and detergents.<br />• Genetic research: Restriction enzymes are used in genetic engineering techniques.<br /><br />AL_mustaqbal University is the first university in Iraq