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4.5.2. The active center of enzymes

The active center of enzymes

The active center is the region of the enzyme that binds to the substrate , and where catalysis occurs. It has the following characteristics:

  • It is a very small part of the total volume of the enzyme.
  • They are made up of amino acids that are close by the folds of the polypeptide chain, even if they were far away in the original chain.
  • It has a three-dimensional structure in the shape of a hole in which the substrate fits.
  • Some amino acids have radicals with chemical affinity for the substrate, which is why they attract it and establish weak bonds with it. When these links are broken, the products are separated from the active center.

The active center of the enzyme is made up of the binding center and the catalytic center, which are usually together. Some amino acids are responsible for binding the enzyme to the substrate through weak bonds (ionic, hydrogen bonds, Van der Waals forces), and others are responsible for enzymatic catalysis, transforming the substrate into a product.

Enzymes are made up of three types of amino acids:

  • Structural amino acids have no dynamic function.
  • Binding amino acids, form weak bonds with the substrate. They constitute the center of fixation of the enzyme.
  • Catalyst amino acids, which are attached to the substrate through covalent bonds, so that in said substrate the molecular structure is weakened, favoring its breakdown. They constitute the catalytic center of the enzyme.