Enzymes have the following characteristics.
• Enzymes are soluble.
• Enzymes are proteins. A number of enzymes require coenzymes to activate them. Coenzymes are non proteins.
• Enzymes are specific. For example , amylases will only act on starch, lactase on lactose, proteases on proteins and lipases on fats.
• Enzymes are organic catalyst. They have the ability to speed up chemical reactions in the body, but they cannot start a reaction. Only small amounts of enzymes are required for any reaction. Unlike inorganic catalysts, enzymes can be inactivated after prolonged action.
• Enzymes are sensitive to temperature. They work best between 35 to 40°C. The optimum (best) temperature is about 37°C. At high temperatures, their three dimensional protein structure which is essential for their activity undergoes irreversible changes. When this happens, the enzymes become inactive and are said to be denatured.
• Enzymes are sensitive to the acidity or alkalinity of their environment. Some enzymes require an acidic medium, some require an alkaline medium while others work best in a neutral medium.
• Enzymes can be inactivated by inhibitors. Some examples of inhibitors are cyanide and mercury.
• many enzymes bring about reversible reactions. These reactions can proceed in both directions under the same or different conditions.
