Online Counseling Resource
YCMOU ELearning Drive…
School of Architecture, Science and Technology
Yashwantrao Chavan Maharashtra
Open University, Nashik – 422222, India
SEP-SBI091-CP1-01
Introduction
Programmes and Courses
SEP–SBI091-U01-CP_01
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Credits
 Academic Inputs by
Sonali Alkari
Faculty YCMOU Nagpur Centre,
Faculty LAD college P.G. D of Biotechnology
Research officer Ankur Seeds Pvt Ltd
[email protected]
[email protected]
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School of Science and Technology, Online Counseling Resource…
How to Use This Resource

Counselor at each study center should use this presentation to deliver
lecture of 40-60 minutes during Face-To-Face counseling.

Discussion about students difficulties or tutorial with assignments should
follow the lecture for about 40-60 minutes.

Handouts (with 6 slides on each A4 size page) of this presentation should
be provided to each student.

Each student should discuss on the discussion forum all the terms which
could not be understood. This will improve his writing skills and enhance
knowledge level about topics, which shall be immensely useful for end
exam.

Appear several times, for all the Self-Tests, available for this course.

Student can use handouts for last minutes preparation just before end
exam.
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Learning Objectives
 After studying this module, you should be
able to :
 Describe Enzymes
 Discuss
historical
Aspects
of
Enzymology;
 Role of enzymes as biocatalysts
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School of Science and Technology, Online Counseling Resource…
Introduction:Enzymes-1
 Living systems make use of energy from the
environment. Many of us, for example,
consume substantial amounts of sucrose—
common table sugar—as a kind of fuel,
whether in the form of sweetened foods and
drinks or as sugar itself.
 The conversion of sucrose to CO2 and H2O in
the presence of oxygen is a highly exergonic
process, releasing free energy that we can use
to think, move, taste, and see.
 However, a bag of sugar can remainon the
shelf
for
years
without
any
obvious
conversion to CO2 and H2O.
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Introduction:Enzymes-2
 Although
this
chemical
process
is
thermodynamically favorable, it is very slow!.
 Yet when sucrose is consumed by a human (or
almost any other organism), it releases its
chemical energy in seconds.
 The difference is catalysis.
 Without catalysis, chemical reactions such as
sucrose oxidation could not occur on a useful
time scale, and thus could not sustain life.
 The reaction catalysts of biological systems: the
enzymes, the most remarkable and highly
specialized proteins.
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Introduction: Enzymes-3
 Enzymes have extraordinary catalytic power, often far
greater than that of synthetic or inorganic catalysts.
 Enzymes, the catalysts of biological systems, are
remarkable molecular devices that determine the
patterns of chemical transformations.
 Enzymes mediate the transformation of one form of
energy into another.
 The most striking characteristics of enzymes are their
catalytic power and specificity.
 Catalysis takes place at a particular site on the
enzyme called the active site.
 Nearly all known enzymes are proteins.
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Role of Enzymes
 Enzymes play a critical role in everyday life.
 Many heritable genetic disorders (diabetes, TaySachs disease) occur because there is a deficiency or
total absence of one or more enzymes. Other disease
conditions (cancer) result because there is an
excessive activity of one or more enzymes.
 Routine medical tests monitor the activity of enzymes
in the blood, and many of the prescription drugs
(penicillin, methotrexate) exert their effects through
interactions with enzymes.
 Enzymes and their inhibitors can be important tools
in medicine, agriculture, and food science.
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Enzymes as Biocatalysts-1
 They have a high degree of specificity for their
substrates, they accelerate chemical reactions
tremendously, and they function in aqueous
solutions under very mild conditions of
temperature and pH.
 Enzymes are central to every biochemical
process.
 Acting in organized sequences, they catalyze
the hundreds of stepwise reactions that
degrade nutrient molecules, conserve and
transform
chemical
energy
and
make
biological
macromolecules
from
simple
precursors.
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Enzymes as Biocatalysts-2
 Through the action of regulatory enzymes,
metabolic pathways are highly coordinated to
yield a harmonious interplay among the many
activities necessary to sustain life.
 In some diseases, especially inheritable
genetic disorders, there may be a deficiency
or even a total absence of one or more
enzymes.
 For other disease conditions, excessive
activity of an enzyme may be the cause.
 Measurements of the activities of enzymes in
blood plasma, erythrocytes, or tissue samples
are important in diagnosing certain illnesses.
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Enzymes as Biocatalysts-3
 Many drugs exert their biological effects through
interactions with enzymes.
 Enzymes are important practical tools, not only in
medicine but in the chemical industry, food
processing, and agriculture.
 In many biochemical reactions, the energy of the
reactants is converted with high efficiency into a
different form.
 For example, in photosynthesis, light energy is
converted into chemical-bond energy through an ion
gradient.
 Enzymes may then use the chemical-bond energy of
ATP in many ways
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Enzymes as Biocatalysts-4
 In mitochondria, the free energy contained in small
molecules derived from food is converted first into
the free energy of an ion gradient and then into a
different currency, the free energy of adenosine
triphosphate.
 The enzyme myosin converts the energy of ATP into
the mechanical energy of contracting muscles.
 Pumps in the membranes of cells and organelles,
which can be thought of as enzymes that move
substrates rather than chemically altering them,
create chemical and electrical gradients by using the
energy of ATP to transport molecules and ions.
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Historical Aspects of Enzymology-1
 Much of the history of biochemistry is the
history of enzyme research.
 Biological catalysis was first recognized and
described in the late 1700s, in studies on the
digestion of meat by secretions of the
stomach, and research continued in the 1800s
with examinations of the conversion of starch
to sugar by saliva and various plant extracts.
 In the 1850s, Louis Pasteur concluded that
fermentation of sugar into alcohol by yeast is
catalyzed by “ferments.”
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School of Science and Technology, Online Counseling Resource…
Historical Aspects of Enzymology
 He postulated that these ferments were inseparable
from the structure of living yeast cells; this view,
called vitalism, prevailed for decades.
 Then in 1897 Eduard Buchner discovered that yeast
extracts could ferment sugar to alcohol, proving that
fermentation was promoted by molecules that
continued to function when removed from cells.
 Frederick W. Kühne called these molecules enzymes.
 The isolation and crystallization of urease by James
Sumner in 1926 provided a breakthrough in early
enzyme studies.
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Historical Aspects of Enzymology-3
 Sumner found that urease crystals consisted
entirely of protein, and he postulated that all
enzymes are proteins.
 In the absence of other examples, this idea
remained controversial for some time.
 Only in the 1930s was Sumner’s conclusion
widely accepted, after John Northrop and
Moses Kunitz crystallized pepsin, trypsin, and
other digestive enzymes and found them also
to be proteins.
 The molecular nature of enzymes was not yet
fully appreciated.
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Historical Aspects of Enzymology-4
 Haldane made the remarkable suggestion that
weak bonding interactions between an
enzyme and its substrate might be used to
catalyze a reaction.
 This insight lies at the heart of our current
understanding of enzymatic catalysis.
 Since the latter part of the twentieth century,
research on enzymes has been intensive.
 It has led to the purification of thousands of
enzymes, elucidation of the structure and
chemical mechanism of many of them, and a
general understanding of how enzymes work.
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What You Learn…
 You have learnt :
 Enzymes,
the
catalysts
of
biological
systems, are remarkable molecular devices
that determine the patterns of chemical
transformations.
 Nearly all known enzymes are proteins.
 Acting in organized sequences, they
catalyze the hundreds of stepwise reactions
that degrade nutrient molecules, conserve
and transform chemical energy and make
biological macromolecules from simple
precursors.
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School of Science and Technology, Online Counseling Resource…
Critical Thinking Questions
1. What are enzymes?
2. Who has coined the term enzyme
and why?
3. Summarize the historical aspects of
enzymology?
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School of Science and Technology, Online Counseling Resource…
Hints For Critical Thinking Question
1. Enzymes, the catalysts of biological systems,
are remarkable molecular devices that
determine
the
patterns
of
chemical
transformations.
2. Frederick W. Kühne based on activity.
3. “ferments”,
Eduard
Buchner
discovery,
Frederick
W.
Kühne,
isolation
and
crystallization and a general understanding of
how enzymes work.
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Study Tips:1
 Book1
 Title: Molecular Cell Biology
 Author: Harvey Lodish, David Baltimore
Publisher:Publishers: W. H. Freeman and
Company
 Book2
 Title: Principles of Biochemistry
 Author: AlbertL Lehninger
 Publisher:CBS Publishers & Distributors
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Study Tips:2
 Book3
 Title: Biochemistry
 Author: Lubert stryer
 Publishers: Freeman International
 Book4
 Title: Biochemistry
 Author: Keshav Trehan
 Publishers: Wiley Eastern
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School of Science and Technology, Online Counseling Resource…
Study Tips
www.en.wikipedia.org
Microsoft Encarta Encyclopedia
http://en.wikipedia.org/wiki/
Wikipedia the free encyclopedia
(www.chem.qmul.ac.uk/iubmb/enzyme).
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School of Science and Technology, Online Counseling Resource…
End of the Presentation
Thank You!
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