Classification of enzyme

Classification of enzyme

Classification of enzyme

Classification of enzyme:

Classification of enzyme is very important to study about Enzymes and their reaction. The Enzymes are classified according to the reaction they catalyze. The classification is shown bellow:

  • Oxidoreductase:

Oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule to another molecule. The transfer of electron means the transfer of hydride of hydrogen atom.


Classification of enzyme
  • Transferases:

Transferases are enzymes that catalyse the transfer of a functional group from a donor molecule to an acceptor molecule. Here Group transfer reactions is occoured.


  • Hydrolases:

Hydrolases are a class of enzymes that catalyzes the hydrolysis of a chemical bond.

For example, an enzyme that catalyzed the following reaction is a hydrolase:

A–B + H2O → A–OH + B–H.

  • Lyase:

Lyase is an enzyme that catalyzes the breaking (an “elimination” reaction) of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure.

  • Example:
  • Ligase:

    Ligase is an enzyme that can catalyze the joining of two large molecules by forming a new chemical bond (Formation of C─C, C─S, C─O, and C─N bonds by condensation reactions coupled to ATP cleavage).

  • Example:Classification of Enzymes
  • Isomerases:

    Isomerases are enzymes that catalyze the isomerization of a molecule. In other words, they facilitate the transfer of specific functional groups

  • Example:

Enzymes are classified according to the type of reaction they catalyze:

Classification of Enzymes

Reaction catalyzed   Example Reactions
Oxidoreductases Oxidation-reduction Lactate dehydrogenase
Transferases Transfer groups of atoms Alanine transferase
Hydrolases Hydrolysis Sucrase
Lyases Add atoms/remove atom to/from a double bond Pyruvate decarboxylate
Isomerases   Rearrange atoms Maleate isomerase
Ligases Use ATP to combine molecules Acetyl-Co A synthetase

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