A brief description about Enzyme, its types,theories abou it and its action mechanism

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JINNAH COLLEGE OF NURSING
__________PRESENTAION___________
ON
ENZYMES
Presentaion made by:
ASAD ALI
8/21/2020 3

4. Objectives:
At the end of this lecture students will be able to:
❑ Define Enzyme and its historical background.
❑ Structure of Enzyme.
❑ Explain the theories presented about Enzyme’s action.
❑ Reaction Mechanism of Enzyme.
❑ Nomenclature and Classification of Enzymes.
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5. CONTINUE……
❑ Functions of Enzyme.
❑ Know about Co-factor, Enzyme Activators and Inhibitors.
❑ Types of Inhibitors.
❑ Factors that Affect the Rate of Enzyme Reaction.
❑ Properties and Importance of Enzymes.
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6. ENZYMES
• Enzymes are biological molecules (typically
proteins) that significantly speed up the rate of
virtually all of the chemical reactions that take place
within cells.
• They are vital for life and serve a wide range of
important functions in the body, such as aiding in
digestion and metabolism.
• Mostly enzymes are proteins in Nature.
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7. SHORT HISTORY OF ENZYME
• Enzyme is a Greek word which means:
En = Inside Zyme = Yeast
➢Ansele Payan (1833): French Chemist
Discovered 1st enzyme --- Diastasis
➢Luis Pasteur:
Glucose Alcohol
so he gave it the name “Ferment”
➢Friedrick Wilheum Kuhne(1877):
Changed the name “Ferment” into “Zymase”.
➢Buchnar(1897):
changed “Zymase” into “Enzyme”.
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Fermentation(in yeast)

8. REACTION MECHANISM
OF ENZYME
Two models were presented to explain action mechanism of
enzyme. i.e:
i. Induced fit model.
ii. Lock and key model.
1. Lock and key model:
❖Emil Fisher (1890-1894)
❑Proposed the model to visualize substrate
and enzyme interaction
❑ Specific lock can be opened by specific key
similarly one enzyme can be convert only specific substrate to product
❑ Lock = Enzyme and key = Substrate
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9. CONTI…….
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INDUCE FIT MODEL:
❖Denial Koshland (1959)
➢ Proposed that Substrate and enzyme induce a
change in active site
➢ It enable enzyme to perform catalytic activity
more perfectly

11. COMPARISON OF BOTH
MODELS
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12. TYPES OF ENZYMES
The biochemical reactions occurring in the
body are basically of 6 types and the enzymes
that bring about these reactions are named
accordingly:
i. Oxidoreductases
ii. Transferases:
iii. Hydrolases
iv. Lyases
v. Isomerases
vi. Ligases

13. CONT….
1. Oxidoreductases:
These enzymes bring about
oxidation and reduction reactions and hence are called
oxidoreductases.
2. Transferases:
These enzymes are responsible for
transferring functional groups from one molecule to
another.

14. CONT….
3. Hydrolases:
Hydrolases are involved in the process of hydrolysis in which
salt is hydrolysed with water to form acid and bases. Example:
Glucose-6-phosphatase that removes the phosphate group from
glucose-6-phosphate, leaving glucose and H3PO4.

15. CONT……
4. Lyases:
These enzymes are involved in the break
down of a complex compound into two or more
simple compounds. This reaction is called
decomposition.
4. Isomerases:
These enzymes catalyze the reactions where a
functional group is moved to another position within
the same molecule such that the resulting molecule is
actually an isomer of the earlier molecule.

16. CONT….
6. Ligases:
These enzymes are involved in the synthesis or addition
reaction in which two simple compounds are reactedwith each
other to form a new complex compound.

17. FUNCTION OR PROPERTIES OF
ENZYMES
• Enzymes are used in very less amount.
• Speed up the reaction.
• Decrease the activation energy of the reactants.
• Do not take part in reaction.
• Remain unchanged after the reaction.
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18. CONTI..…
• Enzymes prevent the abnormal blood clotting
• Drugs like penecilline, Amoxilline ACE inhibitor act as enzymes
inhibitors
• Enzymes helps to build up the new cells.
• Enzymes helps to remove the waste products.
• Enzymes repair the demaged the tissue.
• Enzymes control the inflammation.
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19. COFACTORS
Cofactors are atoms, groups of atoms and molecules that joins with
enzymes altering their shape and making them functional.
One can think of these an “on-off” switch for activating an
enzyme.
Prosthetic Group:
If the cofactor is a non protein like metallic ion (i.e. zinc, copper
or iron) it is referred to as a prosthetic group.
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20. CO-ENZYMES:
Some Co-factors are small organic molecules called co-
enzymes. It’s mostly derived from vitamins and minerals
o Some examples of Coenzymes are : NAD+, FAD+ NADP.
o Absence of some cofactor leads to mineral and vitamins
deficiency diseases
e.g : Lack of Vitamin B Produces beriberi disease.
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21. ENZYME INHIBITORS
Definition:
It is a chemical substance which can block the active site of an enzymes
temporarily or permanently by stopping the activity of the enzyme.
Types:
➢Irreversible inhibitor:
• permanently destroying the globular structure of enzyme
➢Reversible inhibitor:
• Their effected can be reversed by an increase in the concentration of
the substrate.
o Competitive inhibitor
o Non Competitive inhibitor
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22. CONTI….
i. Competitive inhibitor:
It is the type of reversible inhibitor which have structural
similarity with the substrate and can therefore bind to the active site of
the enzyme
They block the active site of the enzyme and prevent the substrate to
reach it.
e.g: Sulphonamid
ii. Non-Competitive inhibitor:
It is also the type of reversible inhibitor which do not resemble the
substrate and therefore do not compete with substrate.
They combined with the enzyme at a point other then the active site are
called allosteric site
E.g: Insecticides, heavy metal ions etc.
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23. FACTORS THAT AFFECT THE
RATE OF ENZYME REACTION
Some of the important factors that can affect the rate of enzyme
action are :
1. Temperature:
2. pH value:
3. Enzyme concentration:
4. Substrate concentration:
5. Activators and Inhibitors:
6. Radiation
7. End-products
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24. CONTI…..
1. Temperature:
• Rate of reaction is directly proportional to the increase in
temperature up to an optimum level
• All enzymes can work at their maximum rate at a specific
temperature called as optimum temperature
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25. CONTI……
1. pH Value:
• Every enzyme functions most effectively in a particular range of ph
known as optimum pH (e.g: mostly 7-8 pH).
• A slight change in PH can change the ionization of the amino acid at the
active site.
• Different enzymes works in different pH
e.g: Pepsin(1.5-1.6), invertase(4.5), urease(7.0), trypsin(7.8-8.7).
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26. CONTI……
3. Enzyme concentration:
• The rate of reaction depends directly on the amount of enzymes
present is a reaction
• By increasing the enzymes molecules more active site will convert
the substrate molecules into product.
• After a certain limited concentration the rate of reaction (enzyme
activity) will no longer depend upon this increase.
4. Substrate concentration:
• Increase in the substrate concentration, also increases the rate of
reaction for a given amount of enzyme.
• However at certain point further increase in substrate.
Concentration would not increase reaction rate.
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27. CONTI……
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29. IMPORTANCE OF
ENZYMES
➢Enzymes are included in most of chemical reaction that take
place in Organisms .
➢Need for reactions that regulate cells Enzymes allow movement
transport materials around the body and move substance in and
out of cells
➢In animals, another important functions of enzymes is to help
digest food
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30. CONTINUED…….
❖Digestive enzymes speed up reactions that breaks
down large molecules of carbohydrate proteins and
fats into smaller molecules that body can use
❖Without digestive enzymes animal would not be able
to break down food molecules quickly enough to
provide the energy and nutreitent they need to survive
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31. SUMMARY ON ENZYME:
Enzyme explaination:
• Most enzymes are proteins except “Ribozyme”
• Speed up reaction by lowering AE
• Enzymes are substrate specific.
• Act as biological catalyst.
• Structure of Enzymes:
• Conrtibution of different scientists in study of enzyme
▪ Ansele Payan (1833): French Chemist
discovered Diastasis.
▪ Luis Pasteur:
1st experiment. Gtucose to alcohol
▪ Friedrick Wilheum Kuhne(1877): German scientist
▪ Buchnar(1897):
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32. CONTI….
• Lock & key Model Induced Fit Model
i. Active site is rigid - Active site slightly Flexible
ii. No modification - E-S Complex-Induced changed
iii. Active site doesn’t change itself - Adjust with Substrate
• Nomenclature of enzyme: suffix “ase” except “pipsin and tripsin”
❖ Named according to the subtract on which it acts.
• Types of Enzymes:
i. Oxidoreductases: oxidases, oxygenases and peroxidases
ii. Transferases: Transcorboxylases and transmethylases
iii. Hydrolases: Esterases,phosphatases and peptidases.
iv. Lyases: Decorboxylases,deaminases and synthases
v. Isomerases: Epimerases and mutases
vi. Ligases (molecular glue): amylaseand, lipase etc
• Functions of Enzymes:
Speed: can digest 6 lac molecules of H2O in 1 second.
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33. CONTI….
• Enzyme activators:
• Co-factor: …. “on-off switch”
• Co-enzyme: organic … NAD+ etc
• Prosthetic group: …. Non protein….
• Enzyme inhibitors:
▪ Irreversible inhibitors
▪ Reversible inhibitors
✓ Competitive reversible inhibitors: Sulphonamid
✓ Non-competitive reversible inhibitors. Insecticides
• Factors that Affect the Rate of Enzyme Reaction:
1. Temperature:
2. pH value:
3. Enzyme concentration:
4. Substrate concentration:
• Importance Of Enzymes
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“Talent wins games, but teamwork and intelligence wins
championships.”
“The mINd Is NOT a vessel TO be
fIlled, buT a fIre TO be kINdled.”

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