Enzimë

Enzimë, the Albanian term for enzymes, are biological catalysts that accelerate chemical reactions in living organisms. Most enzimë are proteins, but a minority are RNA molecules with catalytic activity known as ribozymes. Enzimë are highly specific for their substrates and for the reactions they catalyze, often acting on a single substrate or a narrow group of related substrates.

Enzimë act by binding substrates at the active site to form an enzyme-substrate complex. Through induced fit and stabilization of the transition state, they lower the activation energy of a reaction. They employ catalytic strategies such as acid-base catalysis, covalent catalysis, and metal ion catalysis. The activity of enzimë depends on factors like temperature, pH, and the presence of cofactors; outside optimal conditions they may denature or lose activity.

Enzimë are classified by the type of chemical reaction they catalyze into several broad classes, and many carry an EC (enzyme commission) number. Cofactors such as metal ions or organic molecules (coenzymes) are often required. Enzimë activity is regulated by cellular signals through allosteric effects, covalent modification, or changes in gene expression; feedback inhibition is a common regulatory mechanism.

Michaelis-Menten kinetics describe how the rate of an enzimë-catalyzed reaction depends on substrate concentration, characterized by parameters Km and Vmax. Inhibitors can affect enzymes competitively, noncompetitively, or uncompetitively, altering substrate binding or catalysis.

Role and applications: Enzimë are essential in digestion, metabolism, DNA replication, and many other biological processes. Industrial uses include food processing, textile and detergent applications, pharmaceutical synthesis, and biofuel production. Clinically, abnormal enzimë activity serves as biomarkers for disease, and enzyme therapies and diagnostics rely on their properties.