Enzymes are biological catalysts that are usually proteins and help speed up chemical reactions in living organisms. They are classified into six main categories based on the type of reaction they catalyze: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Each enzyme has a systematic name based on the reaction it catalyzes and the substrates involved, and is assigned an EC number for classification. Enzymes play an essential role in carrying out cellular processes.

1. 6th
SEMESTER – BOTANY
1
Presented By,
Dr.Thirunahari Ugandharna

2. Introduction & History
● Enzyme, in Greek means in living (en= in, zyme =
living).
● Biocatalysts or Organic catalysts, usually high
molecular weight proteins (exception- Ribozymes or
RNAenzymes).
● Coined by Kuhne in 1878.
● First enzyme extract from Yeast cells by Buchner (1897).
● First purified enzyme is urease, by James B.
Summer (1926).
2

3. Definition
 An enzyme is a protein or RNA produced by living cells, which is
highly specific and highly catalytic to its substrates.
 Enzymes are a very important type of macromolecular biological
catalysts.
 Due to the action of enzymes, chemical reactions in organisms
can also be carried out efficiently and specifically under mild
conditions.
• ఎంజైమ్ అనేది జీవ కణాల దాారా ఉత్పత్తి చేయబడిన ప్రో టీన్ లేదా
ఆర్‌ఎన్్‌ఏ, ఇది చాలా నిరదిష్టంగా మరదయు దాని ఉపరదత్లాలకు అత్యంత్
ఉత్పేరేరకంగా ఉంట ంది.
• ఎంజైములు స్థూ ల కణ జీవ ఉత్పేరేరకాల యొకక చాలా ముఖ్యమైన రకం.
ఎంజైమ్్‌ల చరయ కారణంగా,
• జీవులలో రసాయన పోత్తచరయలు స్మరూవంత్ంగా మరదయు పోత్పేయకంగా
త్పేలికప్ాటి పరదస్థూత్ులలో కూడా నిరాహంచబడత్పాయి.

5. Nomenclature
 The nomenclature of enzymes is derived from their substrates or the
catalyzed chemical reactions, and "ase" is usually added as a suffix.
 Enzymes can be indexed with letters and numbers according to
International Union of Biochemistry and Molecular Biology:
 The letter EC plus four numbers representing four elements.
 The first number represents enzymes that are classified according to
the mechanism of enzymatic reaction.
 ఎంజై మ్ల నామకరణం వాటి ఉపరితలాల నండి లేదా ఉత్ప్రేరక రసాయన
పర తిచరయల నండి తీసుకోబడింది మరియు "యాస్" సాధారణంగా పర తయయం వలె
జోడించబడుతంది.
 ఇంటర్నేషనల్ యూనియన్ ఆఫ్ బయోకెమిస్ట్ర ే అండ్ మాలిక్యయలర్ బయాలజీ పర కారం
ఎంజై మ్లన అక్షరాలు మరియు సంఖ్యలతో సూచంచవచ్చు:
 అక్షరం EC పల స్ నాలుగు మూలకాలన సూచంచే నాలుగు సంఖ్యలు.
 మొదటి సంఖ్య ఎంజై మ్ పర తిచరయ యొకక విధానం పర కారం వర్గీ కరించబడిన
ఎంజై మ్లన సూచసుత ంది.

7. Enzymes are Biological Catalysts
Enzymes are proteins that:
● Increase the rate of
reaction by lowering the
energy of activation.
● Catalyze nearly all the
chemical reactions taking
place in the cells of the
body.
● Have unique three-
dimensional shapes that fit
the shapes of reactants.
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8. Activation Energy
Think of activation energy as the
BARRIER
required to make a product.
Most stable product is the one with
the lowest
energy.
Most reactions require a “push”
to get them
started! “Push” is called “energy
of activation” for
reaction - Also represented byEA
8

9. Trivial Names of Enzymes
The name of an enzyme:
● Usually ends in –ase.
● Identifies the reacting substance. For example,
sucrase catalyzes the reaction of sucrose.
● Describes the function of the enzyme. For example,
oxidases catalyze oxidation.
● Could be a common name, particularly for the
digestion enzymes such as pepsin and trypsin.
9

10. Classification
 According to the type of reactions that the enzymes catalyze,
enzymes are classified into seven categories, which are
oxidoreductases, transferases, hydrolases, lyases, isomerases,
ligases, and translocases.
 Oxidoreductases, transferases and hydrolases are the most
abundant forms of enzymes.
 Individual enzyme classes are further classified systematically
based on the chemical name of the substrate and its reaction
mechanism.
ఎంజైమ్్‌లు ఉత్పేరేరకపరదచే పోత్తచరయల పోకారం, ఎంజైమ్్‌లను ఏడు వరాా లుగా
వరగాకరదంచారు, అవి ఆకసిడొరకటటస్, టరో న్ి్‌ఫేరటస్ెస్, హైడరోలేజస్, లైస్ెస్,
ఐసర మరటస్ెస్, లిగటస్ మరదయు టరో న్ి్‌లోకటస్ులు. ఆకసిడరరడ్కటటస్,
టరో న్ి్‌ఫేరటస్ెస్ మరదయు హైడరోలేజస్ ఎంజైమ్్‌ల యొకక అధిక రూప్ాలు.
వయకసిగత్ ఎంజైమ్ త్రగత్ులు ఉపరదత్లం యొకక రసాయన పేరు మరదయు
దాని పోత్తచరయ విధానం ఆధారంగా కరమపద్ధత్తలో వరగాకరదంచబడత్పాయి.

11. IUB Classification of Enzymes
● Enzymes are classified according to the reaction
they catalyze.
Class
● Oxidoreductases
● Transferases
● Hydrolases
● Lyases
1
1
● Isomerases
● Ligases
Reactions catalyzed
Oxidation-reduction
Transfer groups of atoms
Hydrolysis
Add atoms/remove atoms
to/from a double bond
Rearrange atoms
Use ATPto combine
molecules

14. Systematic Name
 According to the International union Of Biochemistry an
enzyme name has two parts:
 -First part is the name of the substrates for the enzyme.
 -Second part is the type of reaction catalyzed by the
enzyme.This part ends with the suffix “ase”.
 Example: Lactate dehydrogenase
 ఇంటరటేష్నల్ యూనియన్ ఆఫ్ బయోకమిస్్టీ పోకారం ఎంజైమ్
పేరుకు రండు భరగాలు ఉనాేయి:
 మొద్టి భరగం ఎంజైమ్ యొకక ఉపరదత్లాల పేరు. రండవ
భరగం ఎంజైమ్ దాారా ఉత్పేరేరకమయియయ రకం.
 ఈ భరగం “యాస్” అనే పోత్యయంత్పో ముగుస్ుి ంది. ఉదాహరణ:
లాకటటట్ డీహైడరోజినేస్

15. EC number
 Enzymes are classified into six different groups according to
the reaction being catalyzed.
 The nomenclature was determined by the Enzyme
Commission in 1961 (with the latest update having occurred
in 1992), hence all enzymes are assigned an “EC”number.
 The classification does not take into account amino acid
sequence (ie, homology), protein structure, or chemical
mechanism.
 పర తిచరయన ఉత్ప్రేరకపరచడం పర కారం ఎంజై మ్లన ఆరు వేర్నేరు సమూహాలుగా
వర్గీ కరిసాత రు.
 నామకరణం 1961 లో ఎంజై మ్ కమిషన్ నిరణ యంచంది (తాజా నవీకరణ 1992 లో
సంభవించంది), అందువలల అనిే ఎంజై మ్లక్య “EC” సంఖ్య కేటాయంచబడుతంది.
 వర్గీ కరణ అమై నో ఆమల శ్రే ణి (అనగా హోమోలజీ), ప్రర టీన్ నిరాాణం లేదా రసాయన
యంతార ంగానిే పరిగణనలోకి తీసుకోదు.

16. The Six
Classes●EC1. Oxidoreductases
●EC2. Transferases
●EC3. Hydrolases
●EC4. Lyases
●EC5. Isomerases
●EC6. Ligases

17. EC 1. Oxidoreductases
● Catalyze the transfer of hydrogen or oxygen atoms or
electrons from one substrate to another.
● Since these are ‘redox’ reactions, an electron
donor/acceptor is also required to complete the reaction.
AH2 +B → A+ BH2
Ex. Oxidases, Dehydrogenases, Reductases.
 హైడరోజన్ లేదా ఆకసిజన్ అణువులను లేదా ఎలకాటా నలను ఒక ఉపరదత్లం నుండి
మరొక ఉపరదత్లానికస బదిలీ చేయడానిే ఉత్పేరేరకపరచండి.
 ఇవి ‘రడాక్సి’ పోత్తచరయలు కాబటిట, పోత్తచరయను పూరది చేయడానికస ఎలకాటా న్ దాత్ /
అంగగకరదంచేవారు కూడా అవస్రం

18. EC 2. Transferases
 Catalyze group transfer reactions, excluding
oxidoreductases (which transfer hydrogen or oxygen
and are EC1). These are of the general form:
 A-X + B↔ BX+A
 Ex: Transaminases (transfer amino group),
Kinases (transfer Phosphategroup)
 స్మూహ బదిలీ పోత్తచరయలను ఉత్పేరేరకపరచండి, ఆకసిడొరటడకటటజ్‌లను
మినహాయించి (ఇవి హైడరోజన్ లేదా ఆకసిజన్్‌ను బదిలీ చేసాి యి
మరదయు ఇవి EC 1). ఇవి సాధారణ రూపంలో ఉంటరయి:

19. EC 3. Hydrolases
●Catalyze hydrolytic reactions.
Includes.
● A-X + H2O ↔ X-OH +A-H
●Ex: lipases, esterases, Amylases,
peptidases/proteases, etc.

20. EC 4.
Lyases Catalyze non-hydrolytic (covered in EC 3) removal of
functional groups from substrates, often creating a
double bond in the product; or the reverse reaction, ie,
addition of function groups across a double bond.
A- X +B-Y →A=B +X-Y
Ex: Decarboxylases, Aldolases, Dehydrases,
Deaminases, Synthases, etc.
 నాన్-హైడరోలైటిక్స (EC 3 లో కపపబడి ఉంట ంది) కసరయాత్మక
స్మూహాలను ఉపరదత్లాల నుండి త్పొలగదంచడం, త్రచథ
ఉత్పత్తిలో డబుల్ బంధానిే స్ృష్థటస్ుి ంది;
 లేదా రదవరి రదయాక్షన్, అనగా, డబుల్ బరండ్ అంత్టర ఫంక్షన్
స్మూహాల కలయిక.

21. EC 5. Isomerases
● Catalyzes isomerization reactions, including
epimerizations andcis-trans
● isomerizations.
A→A’
Ex: Isomerases (Cis-Trans),
Epimerases (D—L)

22. EC 6. Ligases
● Catalyzes the synthesis of various (mostly C-X) bonds,
coupled with the breakdown of energy- containing
substrates, usually ATP .
A + B → A-B
ATP → ADP+iP
Ex: Synthetases, Carboxylases
వివిధ్‌(ఎకుకవగా్‌స్థ-ఎక్సి) బంధాల్‌స్ంశ్లలష్ణను్‌ఉత్పేరేరకపరుస్ుి ంది, శకసి-
కలిగదన్‌ఉపరదత్లాల్‌విచిినేంత్పో్‌ప్ాట , సాధారణంగా్‌ఎటిపథ.

24. Classification of Enzymes:
Oxidoreductases and Transferases
24

25. Classification: Hydrolases and
Lyases
25

26. Classification: Isomerases and
Ligases
26

28. Active
SiteThe activesite:
● Is a region within an
enzyme that fits the
shape of molecules
called substrates.
● Contains amino acid R
groups that align and
bind the substrate.
● Releases products
when the reaction is
complete.
28

31. Enzyme
SpecificityEnzymes may recognize and catalyze:
● Asingle substrate.
● Agroup of similar substrates.
● Aparticular type ofbond.
31

33. Mechanism of
Enzyme Catalyzed
Reactions● The proper fit of a substrate (S) in an active site
forms an enzyme-substrate (ES) complex.
E + S ES
● Within the ES complex, the reaction occurs to
convert substrate to product (P).
ES E+ P
● The products, which are no longer attracted to
the active site, are released.
● Overall, substrate is convert to product.
E + S ES E+ P
33

34. Mechanism of Enzyme
Action
34

35. 35

36. Example of An Enzyme Catalyzed
Reaction
36

37. Mechanism of Enzyme Action:
1.Lock-and-Key Model
In the lock-and-key model of enzyme action:
● The active site has a rigid shape.
● Only substrates with the matching shape can
fit.
● The substrate is a key that fits the lock of the
active site.
37

38. 2. Induced-fit
ModelIn the induced-fit model of enzyme action:
● The active site is flexible, not rigid.
● The shapes of the enzyme, active site, and
substrate adjust to maximum the fit, which
improves catalysis.
● There is a greater range of substrate specificity.
38

39. Isoenzym
es● Isoenzymes
catalyze the same
reaction in
different tissues
in the body.
● Lactate
dehydrogenase,
which converts
lactate to
pyruvate, (LDH)
consists of five
isoenzymes.
39

40. Temperature and Enzyme
ActionEnzymes:
● Are most active at an
optimum
temperature (usually
37°Cin humans).
● Show little activity at
low temperatures.
● Lose activity at high
temperatures as
denaturation occurs.
40

41. pH and Enzyme
ActionEnzymes:
● Are most active at
optimum pH.
● Contain R groupsof
amino acids with
proper charges at
optimum pH.
● Lose activity in low or
high pH as tertiary
structure is
disrupted. 41

42. Optimum pH
Values● Most enzymes of the body have an optimum pH
of about 7.4.
● In certain organs, enzymes operate at lower and
higher optimum pH values.
42

43. Enzyme
Concentration● The rate of
reaction increases
as enzyme
concentration
increases (at
constant substrate
concentration).
● At higher enzyme
concentrations,
more substrate
binds with
enzyme. 43

44. Substrate
Concentration● The rate of reaction
increases as
substrate
concentration
increases (at
constant enzyme
concentration).
● Maximum activity
occurs when the
enzyme is
saturated.
44