biochemistry

1. DPT 3RD SEMESTER
Biochemistry
CLASSIFICATION AND
PROPERTIES OF ENZYME

2. Classification
6 classes:
 Oxidoreductases
 Transferases
 Hydrolases
 Lyases
 Isomerases
 Ligases

3. Oxidoreductases
 This class belongs to catalyze
oxidation-reduction reaction
 Reduction= addition of H+
 Oxidation = removal of H+
 AH2 + B A + BH2
 Example: oxidases, dehydrogenases ,
reductases

5. Transferases
 Transfer chemical group of one molecule to
another or to another part of the same molecule
 Catalyze group transfer reactions, excluding
oxidoreductases
 A-X + B BX + A
 EXAMPLE: transaminases ( transfer amino group
)
 Kinase(transfer phosphate group)

6. Hydrolases
 Catalyze hydrolytic reaction
 These enzymes catalyse the
hydrolytic cleavage of C-O,C-N ,C-C
and some other bonds .
 A-X + H2O X- OH +A-H
Example: lipase
Amylase

7. Lyases
 Catalyze non- hydrolytic . Catalyzes the
breaking of various chemical bond i.e C-C, C-N
or also catalyze the addition to C=C , C=O
,C=N
 A-X + B- Y A= B + X- Y
 Example : decarboxylases , dehydrases

8. Isomerases
 Convert a molecule from one isomer
to another .Catalyzes isomerization
reaction”
 A A’
 EX: isomerases
 Epimerases

9. Ligases
 Catalyzes the synthesis of various
bonds, coupled with the breakdown of
energy containing substrates , usually
ATP
 A+ B A- B
ATP ADP +ip
Example: synthetases
Carboxylases