EXCELLENCE IN HIGHER
Directed By:- Dr.Surbhi garde
Submitted By:-Namita ughade
This is to certify that Namita ughade student of
Institute for excellence in higher education
Bhopal has completed the assignment in
Enzymes and it’s classification towards the
partial fulfillment of Bsc chemistry Honours
degree as Prescribed by the institution.
The assignment is in record of authentic work
carried by her.
I have taken efforts however,it would not have
been possible without the kind support and help
of my teacher and Institution.
I thank my god for providing me with everything
that this, required in completing this assignment.
I am highly indebted to my teacher Dr. Surbhi
Garde Ma’am for her guidance and constant
I am very thankful to everyone who supported
me in this assignment.
Enzymes - Introduction
Enzymes are biocatalysts present in cells that speed up
biochemical reactions without getting itself destroyed in
All types of biochemical reactions in the cell require
Enzymes are typically proteins.
Certain types of RNAcan also serve as catalysts. These
RNAmolecules are called ribozymes and DNAzymes.
Nomenclature and Classification of Enzymes
Enzymes are classified according the report of a Nomenclature
Committee appointed by the International Union of Biochemistry.
This enzyme commission assigned each enzyme a systematic name and
a code number, called enzyme commission (EC) number.
: Alcohol dehydrogenase
: Alcohol: NAD+ oxidoreductase
: EC 126.96.36.199
Nomenclature and Classification of
The code numbers, prefixed by EC, which are now widely in use,
contain four elements separated by points, with the following
(i) the first number shows to which of the six main classes the enzyme
(ii) the second figure indicates the subclass,
(iii) the third figure gives the sub-subclass,
(iv)the fourth figure is the serial number of the enzyme in its sub-
Nomenclature and Classification of Enzymes
Example: EC 188.8.131.52 refers to the enzyme alcohol dehydrogenase (common
Its systematic name is alcohol : NAD+ oxido reductase.
It catalyses the oxidation of alcohol to an aldehyde or ketone.
Reaction: an alcohol + NAD+ an aldehyde or ketone + NADH + H+
First digit 1 indicates the major class oxidoreductase
Second digit 1 indicates the subclass acting on CH-OH group of donors
Third digit 1 indicates the sub-subclass NAD+ as the electron acceptor
Fourth digit 1 indicates the serial number of the enzyme alcohol
Enzyme - Classification
Enzymes are classified into six categories (EC number classification)
by the International Union Of Biochemists (IUB) on the basis of the
types of reactions that they catalyze:
EC 1 Oxidoreductases,
EC 2 transferases,
EC 3 hydrolases,
EC 4 lyases,
EC 5 ligases,
EC 6 isomerases.
Classification of Enzymes
Enzymes involved in oxidation-reduction reactions. Eg.Alcohol dehydrogenase
Enzymes involved in transfer of groups from one molecule to another. Eg.
Enzymes that bring about hydrolysis by addition of water. Eg. Lipase
Enzymes that catalyze the breaking of a chemical bond through means not
involving hydrolysis, and forms a double bond or adds a group to a double bond.
Enzymes involved in all kinds of isomerization reactions. Eg. Phosphohexose
Enzymes catalyzing the joining of two molecules with hydrolysis of ATP. Eg.
Oxidation-reduction (redox) reactions - hydrogen or oxygen atoms
or electrons are transferred between molecules.
Example: dehydrogenases, oxidases, oxygenases and peroxidases
Common name: alcohol dehydrogenase
Systematic name: alcohol:NAD+ oxidoreductase
These enzymes catalyse the transfer of a group between
E.g: transfer of acyl, alkyl, amino, phosphate and
Involves transfer of amino group
These enzymes catalyze reactions that involve the process of
They break single bonds by adding water.
Some hydrolases function as digestive enzymes.
Enzymes that catalyze the breaking of a chemical bond
through means not involving hydrolysis, and forms a double
bond or adds a group to a double bond.
Enzymes involved in all kinds of isomerization reactions.
Example: triosephosphate isomerase and phosphoglucose
Enzymes catalyzing the joining of two
hydrolysis ofATP. Eg. Pyruvate carboxylase
• Pineapple contains enzyme bromelain,
which can digest protein (proteolytic).
• Jell-O® is made of gelatin, a
processed version of a structural
protein called collagen found in many
animals, including humans.
• Collagen = big, fibrous molecule makes
skin, bones, and tendons both strong
• Gelatin you eat in Jell-O ® comes from
the collagen in cow or pig bones,
hooves, and connective tissues.
Meet the Enzyme: Bromelain
Meet the Enzyme: Catecholase
Lemon juice and other acids are used to preserve color
in fruit, particularly apples, by lowering the pH and
removing the copper (cofactor) necessary for the enzyme
catechol + O2 ---------- polyphenol
colorless substrate brown product