CLASSIFICATI
ON OF
ENZYMES
INTRODUCTION TO
ENZYME
WHAT IS ENZYME?
Biological catalysts
Usually a protein, but could be RNA
Accelerate rate of reaction
Do not change the equilibrium
Heat labile, water soluble
Can be precipitated by protein precipitating reagents
Contain 16% weight as nitrogen
Nomenclature and Classification of
As per IUBMB:
First digit- Class
Second digit- Subclass
Third digit- Subgroup
Fourth digit- Particular enzyme
CLASS
3:OXIDOREDUCTASES
OXIDOREDUCATSES
Oxidoreductases are group of enzymes that catalyze
oxidation of one substrate with simultaneous reduction
of another substrate or coenzyme
Example: Alcohol dehydrogenase (EC 1.1.1.1.)
CLASS 2:
TRANSFERASES
THIS CLASS OF ENZYMES TRANSFERS ONE
GROUP (OTHER THEN HYDROGEN) FROM
THE SUBSTRATE TO ANOTHER SUBSTRATE.
THIS MAY BE REPRESENTED AS: A-R + B —> A
+ B-R
EXAMPLE: HEXOKINASE
HEXOSE + ATP —> HEXOSE-6-PHOSPHATE +
ADP
CLASS
3:HYDROLASES
➤
Hydrolases are a class of enzymes that
catalyze the hydrolysis of various
chemical bonds through the addition of
water molecules.
➤
There are several types of hydrolases,
including proteases (which break down
proteins), lipases (which break down
fats), carbohydrases (which break down
carbohydrates), nucleases (which break
down nucleic acids), and phosphatases
(which break down phosphoric esters).
➤
Each type of hydrolase targets a specific
type of substrate and facilitates the
breakdown of these molecules into their
constituent parts.
➤
Substrate: Triglyceride (a type of lipid) Enzyme: Lipase
➤
Reaction: Triglyceride + Water → Glycerol + Three Fatty Acid Molecules
➤
In this reaction, lipase catalyses the breakdown of a triglyceride molecule, which is
composed of glycerol and three fatty acid chains, into glycerol and three separate fatty
CLASS 4:LYASES
➤
Lyases are a type of enzyme involved in
catalyzing reactions that lead to the
breaking of certain chemical bonds within
a molecule without the addition of water
(hydrolysis) or the transfer of electrons
(oxidation-reduction).
➤
Instead, these enzymes facilitate
reactions that form new chemical bonds
or rearrange existing ones.
➤
Pyruvate→ Acetaldehyde + Carbon Dioxide
➤
This reaction involves the removal of a carboxyl group from pyruvate, resulting in the
formation of acetaldehyde and carbon dioxide. Pyruvate decarboxylase, the lyase enzyme
involved in this process, facilitates this reaction without the direct involvement of water or
oxidation-reduction reactions.
CLASS
5:ISOMERASES
➤
Isomerases are a class of enzymes that
catalyze the conversion of one isomer
into another by rearranging atoms within
a molecule.
➤
This catalytic activity results in the
structural rearrangement of the molecule
without changing its overall composition.
Isomerases play essential roles in various
biological processes, including
metabolism and biosynthesis.
➤
They are classified under EC number 5 in
the Enzyme Commission (EC)
classification system. Examples of
isomerases include racemases,
epimerases, and mutases, each
facilitating specific types of isomerization
reactions.
➤
Triosephosphate isomerase deficiency is
a disorder characterized by a shortage of
red blood cells (anemia), movement
problems, increased susceptibility to
infection, and muscle weakness that can
affect breathing and heart function ,
progressive severe neurological disorder.
➤
Triosephosphate isomerase (TPI)
deficiency is a severe autosomal
recessive inherited multisystem disorder
of glycolytic metabolism characterized by
hemolytic anemia and
neurodegeneration.
CLASS 6:LIGASES
➤
Ligases are enzymes that catalyze the
joining (ligation) of two molecules by
forming a covalent bond.
➤
Function:Essential for DNA repair,
replication, and protein synthesis by
connecting fragmented molecules.
➤
Mechanism:Utilizes ATP to energize the
ligation process, creating a bond between
specific functional groups.
CLASS
7:TRANSLOCASES
➤
Translocases, a class of membrane
proteins, aid the movement of molecules
across cell membranes.
➤
Types:Uniporters, Symporters, and
Antiporters facilitate the transport of
substances based on concentration
gradients.
➤
ATP Involvement:Some translocases, like
ABC transporters, utilize ATP for energydependent transport.
➤
Examples:GLUT proteins facilitate
glucose transport; Sodium-Potassium
pump maintains ion balance.Biological
➤
Significance:Crucial for nutrient uptake,
ion homeostasis, and overall cellular
function.
THANK YOU!
Presented by:
Maryam
Muskaan Singh
Muskan
Naisha Jha
Nikita