Nomenclature and Classification of enzyme

The Nomenclature committee of International Union Of Biochemistry and Molecular Biology (IUBMB) adopted rules in 1992 for the systematic Classification and designation based on reaction specificity.
Every enzyme consists of a code of the letters “EC” followed by four numbers separated by periods.
The first digit defines the general type of reaction catalysed by the enzyme and ranges from one to six.
The second figure indicates the subclass.
The third figure gives the sub-subclass.
The fourth figure is the serial number of the enzyme in its sub-subclass.

1. Nomenclature And classification of Enzymes Presented by .. Fizza Mehwish 5 th semester Bs biotechnology Department of BiotechnologY University of Science & Technology, Bannu

2. Enzyme Definition Enzymes are proteins that function as biological catalyst. It speed up the chemical reactions without being consumed and can be reused to obtain maximum product.

3. Nomenclature The Nomenclature committee of International Union Of Biochemistry and Molecular Biology (IUBMB) adopted rules in 1992 for the systematic Classification and designation based on reaction specificity. Every enzyme consists of a code of the letters “EC” followed by four numbers separated by periods.
The first digit defines the general type of reaction catalysed by the enzyme and ranges from one to six. The second figure indicates the subclass . The third figure gives the sub-subclass. The fourth figure is the serial number of the enzyme in its sub-subclass.

4. Example..

5. Classification

6. EC.1- Oxidoreductases Catalyze oxidation-reduction reactions where electrons are transferred. These electrons are usually in the form of hydride ions or hydrogen atoms. General reaction;

7. Example..

8. EC.2- Transferases Catalyze group transfer reactions. The transfer occurs from one molecule that will be the donor to another molecule that will be the acceptor. General reaction;

9. Example..

10. Ec.3- Hydrolases Ca talyzes the break down of bond of substrate by using water . When the hydrolase acts on amide, glycosyl, peptide, ester, or other bonds, they not only catalyze the hydrolytic removal of a group from the substrate but also a transfer of the group to an acceptor compound. General Reaction;

11. Example..

12. EC.4- lyases C atalyzes the addition or removal of group from one substrate to another by mechanism other than hydrolysis and creating double bond . General reaction;

13. Example..

14. Ec.5- isomerases Catalyze reactions that transfer functional groups within a molecule so that isomeric forms are produced. These enzymes allow for structural or geometric changes within a compound. General reaction;

15. Example..

16. Ec.6- Ligases Catalyze the synthesis of two molecular substrates into one molecular compound with the release energy. These reactions are coupled to the cleavage of ATP. General reaction;

17. Example..

18. Ec.7- Translocases Catalyze the movement of ions or molecules across membranes or their separation within membrane . General reaction; AX + B side 1 || = A + X + || B side 2

19. Example.. A clear example of an enzyme that follows this scheme is  H+-transporting two-sector ATPase: ATP + H2O + 4 H+side 1 = ADP + phosphate + 4 H+side 2

20. Questions Why is systematic naming of enzyme important? On what based ,enzymes are classified? What is meant by EC ? What is the function of transferase? Differentiate between hydrolase and lyase? Which class of enzyme involved all digestive enzyme? What is meant by Isomer? DNA polymerase is a enzyme of what class?