What is an enzyme, and how does it work?
Answer
Enzymes are a special type of protein that speeds up chemical reactions, and aid in metabolism. Metabolism is all of the chemical processes in the body, which includes anabolism and catabolism. Anabolism is building up, or chemical reactions that put things together. Catabolism is breaking down, or chemical reactions that break substances apart. There are many different types of enzymes. Some enzymes build things up in anabolism. Other enzymes help to break things down in catabolism. Our body naturally produces enzymes that are involved in cellular processes. Enzymes can also be found in manufactured products and food. Enzymes work by speeding up chemical reactions in the cell. Enzymes are not destroyed in the reaction but are reusable. An enzyme works as a catalyst. They speed up the rate of a reaction by lowering the activation energy needed for the reaction to occur. This means that when an enzyme is present then the energy needed for that reaction is lower, and the reaction can occur faster.
Each enzyme is specific to a particular chemical reaction. One can identify an enzyme because most of them end in -ase. Lactase, for example, breaks down lactose--a sugar found in milk. Lipase breaks down fats into fatty acids. Protease breaks down proteins into amino acids. How do these enzymes work? Each enzyme has an active site. The active site is a specific shape that will fit a specific substrate. Because of this specificity, we refer to this as a lock and key model. Just as a car key will only open your car, or your house key will only open your house. An enzyme will only fit a substrate for which for which it is responsible for catalyzing the reaction of. Once the substrate attaches to the enzymes for which it fits in the chemical reaction begins. The enzyme will either work to break down the substrate or put together with another substrate. Either way whether the substances are put together or substances are broken down, the substances that are released after the chemical reaction are referred to as a product. An example of this is with the substrate sucrose and its complementary enzyme sucrase. Sucrose has a specific shape that fits the enzyme sucrase. Upon being bound by the substrate, sucrase would lower the activation energy and increase the speed of the catabolism of sucrose. The end products are glucose and fructose; they are released as products. The enzyme sucrase is now available for another reaction.
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