Enzymes are biological catalysts that increase the rate of biochemical reactions by lowering the activation energy required for the reaction to occur. They are essential for the functioning of living organisms, and most biochemical processes rely on enzymes to catalyze the necessary reactions.
Enzymes are typically globular proteins with a specific three-dimensional shape that allows them to bind to specific substrates and catalyze a particular reaction. The enzyme-substrate complex is formed when the enzyme binds to its substrate(s), and the reaction is catalyzed. Enzymes are highly specific, meaning that they typically only catalyze one specific reaction or a group of related reactions.
Enzymes can be classified into several categories based on their structure and function. For example, oxidoreductases catalyze oxidation-reduction reactions, while hydrolases catalyze hydrolysis reactions. Transferases transfer a functional group from one molecule to another, while isomerases catalyze the rearrangement of atoms within a molecule.
Enzymes can also be regulated in several ways. For example, feedback inhibition occurs when the end product of a pathway inhibits the enzyme responsible for its synthesis, preventing excess production. Enzymes can also be regulated by the presence or absence of cofactors, which are molecules that bind to enzymes and are required for their activity. Additionally, enzymes can be regulated by post-translational modifications, such as phosphorylation, which can activate or inhibit the enzyme.
Enzymes have many important applications in industry, medicine, and biotechnology. For example, enzymes are used in the production of food, pharmaceuticals, and biofuels. They are also used in diagnostic tests and therapies for diseases, such as enzyme replacement therapy for patients with genetic disorders that prevent the production of certain enzymes.