Enzymes are biological molecules, typically proteins, that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They are vital for life and serve a wide range of important functions in the body, such as breaking down food for energy and helping in the building of proteins.
Enzymes work by providing an alternative reaction pathway of lower activation energy. They achieve this by binding to the reactant molecules, or substrates, and holding them in such a way as to make the chemical bond-breaking and bond-forming processes more favorable.
Each enzyme is specific for a certain reaction or type of reaction, which means it will only catalyze certain reactions involving specific substrates. This specificity is due to the unique shape and structure of the enzyme, particularly the active site where the substrate binds.
Enzymes are also critical in drug interactions for two primary reasons:
Metabolism: Many drugs are metabolized, or broken down, by enzymes in the liver. This process usually makes drugs more soluble and easier to excrete, but it can also sometimes result in the formation of metabolites that are pharmacologically active or toxic.
Drug Targets: In some cases, enzymes themselves are the targets of drugs. By inhibiting the action of a specific enzyme, a drug can slow down or stop a particular reaction pathway. This is often used to reduce the production of a harmful substance or slow down a metabolic pathway that's too active in a particular disease. For example, many drugs used to treat hypertension work by inhibiting the action of angiotensin-converting enzyme (ACE), reducing the production of a hormone that constricts blood vessels.
Therefore, understanding enzymes is crucial in pharmacology and medicine, as it can help predict how drugs will be metabolized and excreted, how they might interact with each other, and how they can be designed to target specific enzymes to treat disease.