The Importance of enzymes
Enzymes are essential for the maintenance of life in both plants and animals and can also be manipulated for particular use by humans. They are specific globular proteins, meaning they act on a particular substrate and they work best at their “optimum” temperature and pH. Enzymes catalyse reactions that would otherwise take place too slowly in the body and in industry. One method to explain the action of an enzyme on a substrate is the ‘lock-and-key’ hypothesis, by which the active site of the enzyme has a complementary shape to the substrate molecule. Another theory is the ‘induced fit’ hypothesis, by which the presence of the correct substrate ‘induces’ the enzyme active site to alter shape so the substrate does fit.
Enzymes play a vital role in industry. They are incredibly useful because they produce no unwanted products; they reduce pollution because they are biodegradable and help to reduce the amount of energy wasted because they can work effectively at lower temperatures, neutral pHs and atmospheric pressure, therefore reducing cost to the user. Microbial enzymes can be isolated and used in cheese and beer making. To make cheese, rennet, an enzyme preparation, is added to milk contaminated with lactic acid bacteria, which causes the protein casein to coagulate, turning the milk into curd and whey. The curd can then be separated from this and processed further to make cheese.
In biotechnology, enzymes can be used in biosensors, a device that detects a specific substance. An example of a biosensor is the urine glucose test sticks, which contain two enzymes: glucose oxidase and peroxidase. If glucose is present in the urine, then the enzyme glucose oxidase catalyses the oxidation of glucose to gluconic acid and hydrogen peroxide. The peroxidase enzyme then catalyses the reduction of hydrogen peroxide and the oxidation of chromogen, a colourless hydrogen donor compound, to produce water and the oxidised dye. The greater the...