Enzymecatalysis

Enzymecatalysis is the process by which enzymes accelerate chemical reactions by acting as biological catalysts. Most enzymes are proteins, though some RNA molecules possess catalytic activity and are known as ribozymes.

Enzymes work by binding substrates at a highly specific active site to form an enzyme–substrate complex. This interaction orients substrates, can strain bonds, and stabilizes the transition state, thereby lowering the activation energy required for the reaction and increasing the rate of product formation. Catalysis occurs through several mechanisms, including general acid-base catalysis, covalent catalysis, and metal ion catalysis, as well as through improved positioning and induced fit that reduce entropy losses.

Enzymes exhibit high specificity: they typically recognize one or a few substrates and act on them in a stereospecific manner, often yielding a single product. Many enzymes require cofactors such as metal ions or organic molecules (coenzymes), and some require proteolytic activation or are regulated allosterically. Regulation can also occur through covalent modification or the formation of multi-enzyme complexes.

Kinetically, enzymatic reactions are commonly described by Michaelis–Menten kinetics, with parameters such as Km and Vmax; catalytic efficiency is often expressed as kcat/Km. Activity is influenced by environmental conditions, particularly temperature and pH, and is sensitive to inhibitors (competitive, noncompetitive) and various regulatory mechanisms.

Applications of enzymatic catalysis include understanding metabolic pathways, enabling industrial biocatalysis, and informing pharmaceutical development. Knowledge of how enzymes stabilize transition states and control specificity underpins approaches to drug design and disease treatment.