Entsiümid

Entsiümid are chemical compounds that act as catalysts in biological systems. They are predominantly proteins, though some RNA molecules, known as ribozymes, also exhibit enzymatic activity. Enzymes accelerate the rate of biochemical reactions, often by millions of times, by lowering the activation energy required for the reaction to occur. Without enzymes, many essential life processes would proceed too slowly to sustain life.

The catalytic activity of an enzyme is highly specific. Each enzyme typically catalyzes only one or a very small number of related reactions. This specificity arises from the unique three-dimensional structure of the enzyme, particularly its active site. The active site is a region on the enzyme that binds to a specific molecule called a substrate. This binding is often described by the "lock and key" model or the more refined "induced fit" model, where the enzyme's active site changes shape slightly upon substrate binding to achieve optimal interaction.

Once the substrate is bound to the active site, the enzyme facilitates its conversion into products. After the reaction is complete, the products are released from the active site, and the enzyme is free to bind to another substrate molecule. Enzymes are not consumed in the reactions they catalyze, meaning they can be reused. Their activity can be regulated by various factors, including temperature, pH, and the presence of inhibitors or activators. This regulation is crucial for maintaining homeostasis and controlling metabolic pathways within an organism.