Active Site Definition in Biology and Biochemistry

Active Site has its own distinct definition in both Biology and Biochemistry. Being a topic of the sciences, it is actively related to the discussion of enzymes and the reactions they generate along the line.

Conceptually, active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. It consists of amino acid residues that form temporary bonds with the substrate, the binding site, and residues that catalyze a reaction of that substrate, the catalytic site.

Generally, an enzyme molecule has only two active sites, and the active sites fit with one specific type of substrate. An active site contains a binding site that binds the substrate and orients it for catalysis.

The orientation of the substrate and the close proximity between it and the active site is so important that in some cases the enzyme can still function properly even though all other parts are mutated and lose function.

What Do Biology and Biochemistry Say About it?

We also have to look at the true definitions of active site as a topic of scientific importance, that is, we have the duty to discuss the active site definition in Biology and Biochemistry in acceptable terms:

In Biological Terms (Including Biochem)

The active site of an enzyme is the region, which shows the highest metabolic activity by catalyzing the enzyme-substrate complex into the products. The active site is found deep inside the enzyme, which resembles a hole or small depression. An active site is a region combining the specific substrate molecule with the enzyme and thus catalyzing the reaction.

Its specificity of the enzyme is actually due to the active site that allows the binding of a particular substrate. The amino acid residues are present around the active site, which holds the substrate molecule in the right position during biochemical reactions.

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  • Knowing Active Site Enzyme

The enzyme’s active site is the small region, which seems like a cleft or cavity composed of nearly 10-15 amino acid residues.

According to the term, we can define it as a site that activates the complex enzyme to bind with the particular substrate, induces the substrate’s transition state and stabilize the product formation. Thus, the active site merely refers to as the catalytic site.

  • Two Functions of the Active Site

a. Binding Activity

The binding activity is a property of the enzyme’s active site, which increases the binding affinity of the substrate towards an enzyme.

b. Catalytic activity

It is a property of an enzyme’s active site, which aids in the catabolic reaction of the enzyme and substrate to yield product by reducing the activation energy.

Common Features of the Active Site

  • An active site is a specific location found in the enzyme where a substrate binds to catalyze the reaction. It is also called “Enzyme catalytic surface”.
  • About 10-15 amino acid residues combine to form an active site.
  • The active site possesses a specific geometrical shape and chemical signals that allow the specific recognition and binding between an enzyme and a substrate.
  • An active site will allow the specific substrate to bind whose shape complements the shape of an active site. Therefore, a substrate is like is a key that can only fit into the particular lock, i.e. active site.
  • The active site of an enzyme catalyzes many chemical or biological pathways.
  • After the enzyme-substrate complex formation, both substrate and active site change its structural configuration by bending the target bonds and breaking the substrate molecule into a product.
  • Enzymes show catalytic activity, which is due to its active site. It catalyzes a substrate into a product after complementary binding of the substrate with the active site of an enzyme, depending upon the geometric shape, size, charge and stereospecificity etc.
  • The active site of an enzyme induces the “Transition of the substrate”.

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