Your cart is empty

Shop

Quantity: 0

Total: 0,00

0

Enzymes

Enzymes

Enzymes are protein molecules catalysing biochemical reactions. Their activity can be regulated.

Biology

Keywords

enzyme, enzyme protein, active site, substrate, product, inhibition, activation, allosteric inhibition site, allosteric activation site, coenzyme, NADH, NADPH, FADH₂, Acetyl coenzyme A, ATP, catalyst, biochemistry, biology

Related items

Scenes

Reaction

  • enzyme protein - Enzymes are catalysts: they catalyse biochemical reactions, speeding them up several million times by reducing their activation energy. They act by bringing substrates near each other or modifying their spatial structure. Catalysts are not used up in the reaction.
  • active site - The part of the enzyme that catalyses the reaction.
  • substrate
  • product

Inhibition

  • inhibitor - It can bind to the active site, preventing the substrate from binding.

Activation

  • allosteric activation site - When an activator binds here, the spatial structure of the active site changes.
  • activator

Enzymes

  • enzyme protein - Enzymes are catalysts: they catalyse biochemical reactions, speeding them up several million times by reducing their activation energy. They act by bringing substrates near each other or modifying their spatial structure. Catalysts are not used up in the reaction.
  • active site - The part of the enzyme that catalyses the reaction.
  • substrate - During the enzyme reaction one or more of them are converted into one or more products.

Animation

Enzymes are catalysts: they catalyse biochemical reactions, speeding them up several million times by reducing their activation energy. Catalysts are not used up in the reaction.

When two substrates are joined, substrate molecules bind to the active site of the enzyme catalysing the reaction, and the enzyme helps to form a bond between them. Without an enzyme this reaction rarely occurs, as substrates have to collide in a certain spatial formation, with a large amount of energy.

When a substrate molecule is broken down, it binds to the active site of the enzyme protein. The enzyme breaks down the substrate. The strong covalent bond is rarely broken spontaneously, enzymes are needed to speed up the reaction.

The key to the regulation of the enzyme mechanism is enzyme inhibition.

One type of inhibition involves an inhibitor binding to the active site, that is, it competes with the substrate. This is called competitive inhibition.

Another type of inhibition is allosteric inhibition. The inhibitor binds to the allosteric inhibitor site, which causes a conformational change in the active site, preventing it from binding the substrate.

Allosteric activation is the opposite of allosteric inhibition. In its default state, without an activator, the enzyme is inactive. When an activator binds to the allosteric activation site, this changes the spatial structure of the active site, enabling it to bind the substrates and catalyse the reaction.

Coenzymes are molecules that transform during the enzyme reaction: they either release or accept certain substances. When the reaction is complete, the coenzyme becomes detached. Important coenzymes include NADH, NADPH, acetyl-CoA, FADH2, ATP and vitamins.

Narration

Enzymes are catalysts: they catalyse biochemical reactions, speeding them up several million times by reducing their activation energy. Catalysts are not used up in the reaction.

When two substrates are joined, substrate molecules bind to the active site of the enzyme catalysing the reaction, and the enzyme helps to form a bond between them. Without an enzyme this reaction rarely occurs, as substrates have to collide in a certain spatial formation, with a large amount of energy.

When a substrate molecule is broken down, it binds to the active site of the enzyme protein. The enzyme breaks down the substrate. The strong covalent bond is rarely broken spontaneously, enzymes are needed to speed up the reaction.

The key to the regulation of the enzyme mechanism is enzyme inhibition.

One type of inhibition involves an inhibitor binding to the active site, that is, it competes with the substrate. This is called competitive inhibition.

Another type of inhibition is allosteric inhibition. The inhibitor binds to the allosteric inhibitor site, which causes a conformational change in the active site, preventing it from binding the substrate.

Allosteric activation is the opposite of allosteric inhibition. In its default state, without an activator, the enzyme is inactive. When an activator binds to the allosteric activation site, this changes the spatial structure of the active site, enabling it to bind the substrates and catalyse the reaction.

Coenzymes are molecules that transform during the enzyme reaction: they either release or accept certain substances. When the reaction is complete, the coenzyme becomes detached. Important coenzymes include NADH, NADPH, acetyl-CoA, FADH2, ATP and vitamins.

Related items

Transport processes

This animation explains active and passive transport processes occurring through cell...

What size are bacteria?

This lesson presents the structure and classification of bacteria and the role they play...

Bacteria (advanced)

Bacteria are unicellular organisms that have no nuclei and are a few micrometres in length

The structure of prokaryotic and eukaryotic cells

There are two basic cell types: prokaryotic and eukaryotic cells.

Viruses

Viruses consist of protein and DNA or RNA, they reprogram infected cells to produce more...

ADP, ATP

ATP is the main source of energy for cells.

Bacteria (spheres, rods, spirals)

Bacteria occur in a wide range of shapes, including spheres, rods and spirals.

NAD⁺, NADP⁺, NADPH

NAD⁺ is a coenzyme that plays an important role mainly in catabolic processes, while NADP...

Added to your cart.