enzymes enzyme action

1. PATNA UNIVERSITY
DEPARTMENT OF BOTANY
A SEMINAR PRESENTATION ON
“ CLASSIFICATION OF ENZYMES”
SUBMITTED TO: SUBMITTED BY:
Dr. MEENAKSHI SINGH ALKA KUMARI
HOD, DEPARTMENT OF BOTANY ROLL NO.- 04
PATNA UNIVERSITY M.Sc. BOTANY
SEMESTER –II
SESSION: 2020-22

2. ENZYMES
 Enzymes are proteins that functions as
biological catalysts. A catalyst is a substance
that speeds up a chemical reaction but isn’t
changed by the reaction.
 Almost all enzymes are proteins and essential
to life.
 In enzymatic reactions, the molecules at the
beginning of the process are called substrates,
and the enzyme converts them into different
molecules, the products.

3. Classification of Enzymes
 Based on catalyzed reactions, the nomenclature
committee of the International Union of
Biochemistry and Molecular Biology(IUBMB)
recommended the following classifications:
1. OXIDOREDUCTASES
 Catalyze a variety of oxidation-reduction
reactions.
 Act on many chemical groups to add or remove
hydrogen atoms.
 The common name will be dehydrogenase,
reductase.

4. 2. TRANSFERASES
 Transfers chemical groups(acetyl, methyl,
phosphate etc.) from one molecule to another
or to another part of the same molecules.
 Kinases are specialized transferases that
regulate metabolism by transferring phosphate
from ATP to other molecules.

5. 3. HYDROLASES
 Catalyzes hydrolysis reactions where a
molecule is split into two or more smaller
molecules by the addition of water.
 PROTEASES split protein molecules
 HIV Protease is essential for HIV replication
 Caspase plays a major role in apoptosis
 NUCLEASES split nucleic acids(DNA and RNA)
 Based on the substrate type , they are divided
into RNase and DNase.

6. 4. LYASES
 Catalyzes the cleavage of C-C, C-O, C-S and C-
N bonds by means other than hydrolysis or
oxidation.
 Common names include decarboxylase and
aldolase.
5. ISOMERASES
 These enzymes catalyze geometric or structural
changes within one molecule.
 According to type of isomerism, they may me
called cis-trans isomerases, tautomerases etc.

7. 6. LIGASES
 Catalyze reactions in which two chemical groups
are joined(or ligated) with the use of energy from
ATP.
 Examples include peptide synthase, DNA ligase
and RNA ligase.