Enzymology-ppt.pdf

Introduction to enzymology a simple and complete guide for undergraduate

1. Prepared by
Dr. ShraddhaShrivastava
Assistant Professor
Division of Veterinary Biochemistry
Depttof Veterinary Physiology & Biochemistry
Co.V.Sc. & A.H., Jabalpur

2. Index
1. Definition
2. History
3. Importance
4. Properties
5. Classification
6. Different classes of enzymes
7. Nomenclature
8. Individual class of enzymes

3. The study of enzymes is calledenzymology

4. Definition
Biological catalysts
Accelerates the rate of chemical reactions
Capable of performing multiple reactions (recycled)
Final distribution of reactants and products governed
by equilibrium properties
Enzymes are biological catalysts –
Proteins, (a few RNA exceptions)
Orders of magnitude faster than chemical catalysts -
Act under mild conditions (temperature and pressure)
Highly Specific
Tightly Regulated

5. History
Berzelius in 1836 coined the term catalysis (Gk: to
dissolve).
In 1878, Kuhneused the word enzyme (Gk: in yeast) to
indicate the catalysis taking place in the biological
systems.
lsolationof enzyme system from cell-free extract of
yeast was achieved in 1883 by Buchner. He named the
active principle as zymase(later found to contain a
mixture of enzymes), which could convert sugar to
alcohol.
ln1926, James sumnerfirst achieved the isolation and
crystallization of enzyme ureasefrom jack bean.

6. Importance of enzymes
Enzymes are critical for every aspect of
cellular life Enzyme
Cell shape and motility
Surface receptor
Cell cycle
Metabolism
Transcription
Hormone release
Muscle contraction
Protein synthesis

7. Properties
Vitalforchemicalreactionstooccurinthecell
(thebreaking,formingandrearrangingofbonds
onasubstrate(reactant))
Modifiedsubstrate(nowaproduct)often
performsadifferenttask
Consequence:™Transformationofenergyand
matterinthecell™Cell-cellandintracellular
communication™Allowsforcellularhomeostasis
topersist

8. Classification of Enzymes
Enzymescanbeclassifiedusinganumbering
systemdefinedbytheEnzymeCommission.
Thissystemconsistsofafourdigitnumberwhich
classifiesbasedonthetypeofreactionthe
enzymecatalyzes

9. Different classes of enzymes
EC1.Oxidoreductases–Transferelectrons(Redox
reactions)
EC2.Transferases–Transferfunctionalgroups
betweenmolecules
EC3.Hydrolases–BreakbondsbyaddingH2O
EC4.Lyases–Eliminationreactionstoform
doublebonds
EC5.Isomerases–Intramolecularrearangements
EC6.Ligases–Joinmoleculeswithnewbonds

10. Enzyme Nomenclature
EC 3.2.1.1
Type of general reaction Indicates specific
(eg. Hydrolase) enzyme
(eg. Alpha
Subclass of enzyme reaction Amylase)
(eg. glycosidase)
Sub-Subclass of enzyme reaction
 (eg. hydrolyze O glycosylgroups)

11. EC 1. Oxidoreductases
➢Catalyzeoxidation/reduction reactions
Oxidationis thelossofelectronsoranincreasein
the oxidation state of anatom, anion, or of certain
atoms in amolecule.
Reductionis thegainof electrons or adecreasein
the oxidation state of anatom, anion, or of certain
atoms in amolecule.
•Eg. Alcohol dehydrogenaseEC 1.1.1.1.
•Cytochromeoxidase
•Amino acid oxidases

12. EC 2. Transferases
Involved in transfer of functional groups between
molecules
Eg. :-
➢HexokinaseEC 2.7.1.1.
➢Transaminases
➢Phosphorylase

13. EC 3. Hydrolases
Break bonds by adding H2O
Eg:-
Lipase (triacylglycerolacylhydrolaseE.C. 3.1.1.3)
Cholineesterase
Acid and alkaline phosphatase
Pepsin
Urease

14. EC 4. Lyases
Elimination reactions to form double bonds
Eg.-
Aldolase(E.C. 4.1.2.7)
Fumarase
Histidase

15. EC 5. Isomerases
Intramolecularrearangements
Eg:-
TriosephosphaleisomeraseEC 5.3.1.1.
Phosphohexoseisomerase

16. EC 6. Ligases
Join molecules with new bonds
Eg:-
Glutamine synthetaseEC 6.3.1.2.
Succinatethiokinase
Acetyl CoAcarboxylase