This presentation is all about enzymes, its classification and action .

1. ENZYMES

2. ENZYMES
 Enzymes are biological/organic catalysts, mainly
proteins, generated by an organism to speed up
chemical reactions.
 They can be described as any of several complex
proteins that are produced by cells and act as
catalysts in specific biochemical reactions.
 Biological catalysts are those catalysts which are
found in living organisms and they speed up the
metabolic reactions occurring in them.

3. HISTORY OF ENZYMES
Around late 17th and early 18th centuries, the digestion of meat
by stomach secretions and the conversion of starch to sugars by
plant extracts and saliva were known. However, the mechanism by
which this occurred had not been identified.
 In 1833, French chemist Anselme Payen discovered the first
enzyme, diastase.
 In 1877, German physiologist Wilhelm Kühne first used the
term enzyme, which is Greek for "in leaven", to describe this
process. It was later used to refer to nonliving substances,
such as pepsin.
 In 1897, Eduard Buchner found out that juice of ground and
pressed yeasts cells could ferment sugar (well-free
environment)
 In 1926, James Sumner discovered that enzymes are proteins.

4. Wilhelm KühneAnselme Payen
Eduard Buchner James Sumner

5. Enzymes as Biological
Catalysts
 An enzyme may be a Simple protein, or it may be
composed of a protein and non-protein
component called Complex enzyme
 Apoenzyme- protein portion
 Co-enzyme or Prosthetic group- non-protein
portion
 Holo-enzyme- complete enzyme

6. CATALYSTS
 A substance that lowers activation energy of a
reaction so the reaction occurs more quickly but, in
the end, is NOT used up by the reaction is called a
catalyst.

7. ACTIVATION ENERGY
 To start any chemical reaction, energy
is required. The minimum amount of
energy required to start a reaction is
known as it activation energy.
 Activation Energy can be defined as
the energy that must be added to
cause molecules to react with one
another.

9. METABOLISM
Metabolism can be described as a set of biochemical
reactions on which the entire life of living organisms
depend.
 Metabolism= Anabolism + Catabolism
 Catabolism- biochemical reactions in which larger
molecules are broken down.
 Anabolism- biochemical reactions in which larger
molecules are synthesized.

10. Catabolis
Energy is
released
Energy is
gained
Anabolism
This proves that biochemical reactions
are actually energy transfers.

11. Importance of Metabolism:
Metabolism is very essential for carrying out all the life
processes as a disturbed metabolic system can result in
severe diseases and retardation.

12. EXTRACELLULAR AND INTRA
CELLULAR ENZYMES
 Extracellular Enzymes:
Enzymes that are produced inside cells but work outside them.
 Intracellular Enzymes:
Enzymes that work inside the cells.

13. WHAT DO ENZYMES DO?
Some of the ways in which enzymes react are:
 Lowering the activation energy by creating
suitable environment.
 Bringing substrates together in the correct
orientation to react.
It forms Enzyme-substrate complex for a while
during the reactions.

15. CHARACTERISTICS OF ENZYMES
1. Structure
 Enzymes are globular complex protein structures
made up of long linear chains of amino acid
ranging from just 62 amino acid residues in size
to over 2,500 residues.
 Most enzymes are much larger than the
substrates they act on.

16. 2. Reactions
 Unlike most catalysts enzymes are NOT consumed by the reactions
they catalyze.
 During reactions only a small area is directly involved. This area is
called active site.
• It is the region where the substrate is recognized and then
bound for the reaction.
Active Site
• An enzyme substrate is the material upon which an enzyme
acts.
Substrate
• A product is something "manufactured" by an enzyme from its
substrate.
Product

17. 3. Cofactors
There are some enzymes that need additional non protein
molecules/ions called cofactors. Cofactors can be considered "helper
molecules" that assist in biochemical transformations.
Cofactor
Organic
Prosthetic Group: tightly
packed
Coenzyme: loosely attached
Inorganic

18. Enzymes
Inactive
Enzymes
Apoenzymes/
Need cofactors but don’t
have any
Active Enzymes
Holoenzymes:
Apoenzyme+cofactor

19. 4. Metabolic Pathways
When enzymes work together metabolic pathways are
formed. In metabolic pathways a chain or path of
reactions is formed.

20. 5. Inhibitors
Inhibitors are molecules that decrease enzyme activity. Many
drugs and poisons are enzyme inhibitors.

21. Some types of inhibitors are given here:
Competitive :Substrate and inhibitor compete for the enzyme.
Uncompetitive :The inhibitor cannot bind to the free enzyme, only to the
ES-complex.
Non-competitive : can bind to the enzyme at the binding site at the
same time as the substrate, but not to the active site.

22. 6. Activators
Activators have the opposite effect on enzymes. They are the
molecules that increase enzyme activity.

23. Properties of Enzymes
A. Enzymes are active in extremely small amounts
B. True catalysts remain unaffected by the reaction
which they catalyze
C. They have no effect on reaction
thermodynamics
D. Most are highly specific in reactants(substrates)
they bind and the reaction they catalyze

24. How do enzymes differ from
inorganic catalysts?
 Non-enzyme catalysts (acid, metallic
platinum, magnesium) speed up
reactions 100-1000 times
 Enzymes often speed reactions 108-
1013 times; in 1 second, enzyme
accomplish what would normally take
3-300,000 years if the enzymes where
absent

25. WHAT FACTORS AFFECT
ENZYMES?
Enzymes are specific about the working
conditions they are provided.
Changes in the working conditions can change
the type of enzyme, its active site or its speed.
Some of the factors affecting enzyme activity
are discussed here:
1. Temperature
2. pH
3. Substrate Concentration

26. 1. Temperature
Every enzyme works at its best when given a specific
temperature. This temperature is called the optimum
temperature of that enzyme.
The optimum temperature of human enzyme is 37°C.
Reactions are accelerated when the temperature rises to a
certain limit .But when this limit is crossed denaturation of
enzymes takes place.

27. 2. pH
Optimum pH is the range of pH at which enzymes work
best.
A slight change in this optimum pH causes:
i).retardation in enzyme activity.
ii).blockage of enzymes.
iii).ionization of amino acids at the active sites.

28. 3. Substrate Concentration
If enzyme molecules are available in a reaction,
increase in substrate concentration causes increase
in the rate of reaction.
If the ratio of enzymes is less than the ratio of
substrates then the enzymes enter a state called
saturation of active sites.

29. HOW ENZYMES REACT?
 Lock and Key Model:
The enzyme and substrate are specific to each
other. The active site of an enzyme fits together
with a substrate like a lock and key. The key is
the substrate and the lock is the enzyme.

30.  Induced Fit Model:
The enzyme is induced to undergo a slight
alteration in order to fit with the substrate
perfectly.

31. Classification of Enzymes
Bases of Classification
 Nature of activity
 Nature of the substrate
 Type of the reaction they catalyze

32. Classification of Enzymes
The Commission on Enzymes of the
International Union of Biochemistry (CIUB)
classify enzymes as:
1. Hydrolases- affects the cleavage of the
substrate by the addition of water.
Ex. Esterases, carbohydrases, proteases
2. Transferases- they catalyze the transfer of
reactive groups from one compound to
another.
Ex. Transglycosidases, transpeptidases,
transmethylases, transacylases

33. Classification of Enzymes
3. Isomerases- enzymes that catalyze the
interconversion of aldose and ketose
sugars; change the molecular form of the
substrate.
Ex. Phosphoglucoisomerases
4. Oxireductase- enzymes which catalyze
the oxidation-reduction reaction.

34. Classification of Enzymes
5. Lyases- reversely catalyze the renewal of
groups from substrates nonhydrolytically;
removal or addition of a group to a
substrate nonhydrolytically.
Ex. Fumarase
6. Ligases- enzymes that catalyze the linking
together of molecules coupled with the
breaking of pyrophosphate bonds.

35. Practical Uses of Enzymes
Genetic Engineering

36. Uses of Enzymes in Daily
Life
Enzymes are produced in living organisms by cells
but the enzymes used for commercial purposes are
synthetic and made in industries.
Enzymes are used in:
1. Bread production.
2. Fermentation.
3. Paper production.
4. Production of cleaning products (detergent etc.)

37. Some Enzymes And Their Applications
APPLICATION ENZYMES USED
Food processing Amylase,Protease
Baby food Trypsin
Brewing industry Amylase,Protease
Fruit juices Cellulase,Pectinases
Dairy industry Lipases,Lactases
Paper industry Amylase,Ligninase, Xylanases,Cellulases
Biological detergent Amylase,Lipase,Cellulases
Rubber industry Catalase
Photographic industry
Protease

38. The End