Enzyme Classification

Enzyme Classification

1. Hydrolases

   • catalyze substrate hydrolysis reaction - addition of water molecule to a bond causing break
     • Lipases
       • hydrolysis of ester linkages
     • Proteases
       • hydrolysis of peptide linkages
     • Nucleases
       • hydrolysis of sugar-phosphate ester bonds in nucleic acids
     • Carbohydrases
       • hydrolysis of glycosidic bonds
     • Phosphatases
       • hydrolysis of phosphoester bonds

2. Lyases

   • cleavage without hydrolysis
     • dehydrases
       • removal of H2O from substrate
     • decarboxylases
       • removal of CO2 from substrate
     • deaminases
       • removal of NH3 from substrate

3. Oxidoreductases

   • Catalyze redox reactions involving substrate molecules(Addition of O or removal of H)
     • Oxidases
       • Removal of H molecule
     • Reductases
       • Addition of H molecule
     • Dehydrogenases
       • with participation of a coenzy,me (NADH, FADH2, NADPH, FMNH2)

4. Ligases

   • catalyze bonding of 2 substrates with ATP participation
     • synthetases
       • formation of new bond between substrates
     • carboxylases
       • formation of new bond between substrate and CO2; addition of a Carbon to the backbone

5. Transferases

   • transfer of a functional group between two substrates
     • Kinases
       • transfer of a phosphate group (identified with presence of ATP)
     • Transaminases
       • transfer of amino acids

6. Isomerases

   • conversion of a substrate into an isomer
     • racemases
       • D to L isomer
     • mutases
       • conversion into a structural isomer
     • epimerases
       • one sugar epimer to another