Classification of Enzymes

Classification of Enzymes

Enzymes are classified into six group's:

1. Oxidoreductase
2. Transferases
3. Hydrolases
4. Lyases
5. Isomerases
6. Ligases

1) Oxidoreductase:-

• Catalyze oxidation-reduction reactions
• Example:A(reduction) +B(oxidation)➡️A(oxidation) +B(reduction)  
• Oxidases, use oxygen as an e- acceptor
• Dehydrogenases, use molecules like NAD+ as e- acceptor

2) Transferases:-

• Involve transfer of groups from one molecule to another.
• Example:  A-B+C➡️A+B-C
• Transcarboxylases, transfer -COOH groups
• Kinases, transfer phosphate from ATP to a substrate.

3) Hydrolases:-

• catalyze reaction, where bonds are cleaved by adding water.
• Example: A-B + H2O➡️ A-H + B-OH
• Phosphodiesterase, cleaves phosphodiester bonds.
• Peptidase, cleaves peptide bonds of proteins

4) Lyases:-

• They catalyse breaking of C-C, C-O, C-N, C-S and other bonds
• Example: A=B + HX ➡️AX +B-H
• Synthases, link two molecules without involvement of ATP
• Aldolases, remove aldehydes via elimination reaction.

5) Isomerases:-

• Catalyze several types of interamolecular rearrangements to yield isomeric form
• Example: A-B ➡️ BA
• Mutases, intramolecular transfer of functional groups

6) Ligases:-

• Catalyse formation of bonds, energy always coming from ATP hydrolysis.
• Example: A + B + ATP ➡️ A-B + ADP
• Synthetases
• carboxylases