Aktiveringscentra

Aktiveringscentra are specialized regions within molecules, particularly enzymes, where the chemical reaction occurs. These centres are precisely shaped to bind specific reactant molecules, known as substrates. The interaction between the active centre and the substrate is crucial for the catalytic activity of the enzyme. This binding often involves non-covalent interactions such as hydrogen bonds, ionic bonds, and van der Waals forces, as well as sometimes covalent bonds.

The specific three-dimensional arrangement of amino acid residues within the active centre determines its specificity for a particular substrate. This unique fit is often described by models like the lock-and-key model or the induced-fit model. The lock-and-key model suggests a rigid active centre that perfectly complements the substrate, while the induced-fit model proposes that the active centre undergoes a conformational change upon substrate binding to achieve a tighter fit.

Within the active centre, key amino acid residues facilitate the chemical transformation of the substrate into products. These residues can act as acids, bases, nucleophiles, or electrophiles, thereby lowering the activation energy of the reaction. Once the reaction is complete, the products are released from the active centre, allowing it to bind to another substrate molecule and repeat the catalytic cycle. The efficiency and specificity of enzymes are largely attributed to the unique properties of their active centres.