Enzymes Nomenclature

CLASSIFICATION OF ENZYMES

Enzymes are globular protein which speed up of a reaction by reducing activation energy of reaction therefore they are also called as biocatalyst.

In this blog we will studied about how different enzymes were named and how they are classified into different classes;

1-HOW ENZYMES WERE NAMED ?

Enzymes were named in 4 ways:

A- Enzymes are named by adding *ase* to the name of substrate they act.E.g: proteases,lipases etc.

B- Enzymes are also named according to type of reaction they catalyze. E.g reductases etc.

C-Enzymes are also named by focusing on the substrate they act and the reaction they used for catalysis.E.g: DNA -polymerase etc.

D- Some enzymes are named as per substance synthesized.E.g : rhodonase catalyses synthesis of rhodonate from hydrochloric acid and sodium thiosulphate.

2- ClASSIFICCATION OF ENZYMES:

Enzymes are classified according to systematic nomenclature proposed by INTERNATIONAL UNION OF BIOCHEMISTRY IN 1961.

On the basis of this nomenclature enzymes were classified into six categories.

A-OXIDOREDUCTASES:

These enzymes only catalyze those reaction which involve oxidation-reduction reactions.

The enzymes which catalyze the reaction in which electron or H+ ions are add or removed from substrate during a reaction.

EXAMPLES:

Oxygenases,Oxidases,Reductases and peroxidases etc.

B-TRANSFERASES:

These enzymes only catalyze only those reaction in which transfer of group is involved.

EXAMPLES:

Transmethylases,Transcarboxylases,Hexokinases Etc.

C-HYDROLASES:

These enzymes catalyze only those reactions in which breakdown of molecules occurs with addition of water.

EXAMPLES:

Esterases (Breakdown of ester),Peptidases(breakdown of peptide bond),Renin ,Trypsin etc.

D-ISOMERASES:

These enzymes bring about intra molecular rearrangements of atoms in molecules and thus forming one isomer from other.

EXAMPLE:

Epimerases and Mutases etc.

E-LYSASES:

These enzymes catalyze only those reaction in which addition or removal of double bond occurs during a reaction.

EXAMPLES:

Demethylases and Deaminases etc.

F-LIGASES:

These enzymes catalyze only those reactions in which formation of bonds occur during a reaction.For these reactions energy is supplied by ATP hydrolysis.

EXAMPLES:

Polymerase enzymes are best examples of ligases.

IMPORTANT MCQS IN THIS TOPIC:

1-The systematic nomenclature of enzymes was proposed in:

Answer: 1961

2-According to systematic nomeclature enzymes were classified into_groups:

Answer: SIX(6)

3-The transfer of double bonded oxygen from Carbon 1 to Cabon 2 is catalyzed by _class of enzymes:

Answer: ISOMERASES

4-Which class of enzymes catalyze reaction in which transfer of group occurs:

Answer: TRANSFERASES

5-Epimerases Enzymes are belong to _Class of enzymes: