1. UNIT 7 ENZYMOLOGY

2. Learning Objectives Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

4. Learning Objectives Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

5. The Role of Enzymes
Biological catalysts brings chemical
reaction
Produced by living organisms
Present in very small amounts in cells
Functions in the body: (catalyzed & controlled by enzymes)
Digestion
Breathing
Synthesis and breakdown of CHO, COOH & CHON

6. Substrate a substance on which the enzymes acted on it converted to product/s.
-ase (how the enzymes are named) “Acts”
E.g. Lactase - enzyme Lactose - substrate forming the products (glucose + galactose)

7. All enzymes are proteins it follows the physical and chemical reaction of proteins.
They are heat labile
Soluble in water
Precipitated by protein precipitating reagents (e.g. ammonium sulphate or trichloroacetic acid)
Contain 16% weight nitrogen

8. Learning Objectives State the general properties of enzymes
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

9. General Properties of Enzymes
All enzymes are proteins
They accelerate the reaction, but
Do not alter the reaction equilibrium
Not consumed in overall reaction
Required only in very small quantities
They have enormous power for catalysis

10. Enzymes are highly specific for their substrate
Enzymes posses active sites at which interaction with substrate takes place
Enzymes lower activation energy
They form substrate complex as intermediates during their action
Some enzymes are regulatory in function

11. Learning Objectives Classify enzymes
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

12. CLASSIFICATION OF ENZYMES
1. OXIDOREDUCTASES
(one compound oxidized, another is reduced)
3. HYDROLASES
(hydrolysis of esters, ether, peptide / glycosidic bond)
> Enzyme helps in hydrolysis of chemical bonds by addition of water molecules
2. TRANSFERASE
(transfer group containing C,N,or S from one substrate to another substrate)

13. CLASSIFICATION OF ENZYMES
OXIDOREDUCTASES
e.g. tyrosinase,urease,
catalase, peroxidase
HYDROLASES
e.g. esterases, peptidases
TRANSFERASE
e.g. transaminases, hexokinases
Lactate dehydrogenase
Pyruvate
Lactate
NAD NADH+H+
Serine dehydrogenase
Serine
Glycine
Methyl transferase
Urease “Split”
Urea + H2O CO2 + 2NH3

14. CLASSIFICATION OF ENZYMES
4. LYASES
(catalyze the addition or removal of groups without hydrolysis, oxidation or reduction producing double bonds)
6. LIGASES
(also called as synthesases link two substrates together by pyrophosphate bound in ATP)
5. ISOMERASES
(produce geometric or position isomers of substrates by intermolecular rearrangement)

15. CLASSIFICATION OF ENZYMES
LYASES
e.g. decarboxylases, carboxylases, carbonic anhydrase
LIGASES
e.g. glutamine synthetase
ISOMERASES
e.g. reacemases, epimerases, isomerases
Pyruvate
Pyruvate
Acetaldehyde + CO2
Dehydrogenase
Mutase
Succinyl CoA
Methyl Malonyl CoA
Pyruvate Carboxylase
Pyruvate Oxaloacetate
ATP ADP + Pi

16. Explain enzyme specificity
Learning Objectives
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

17. SUBSTRATE SPECIFICITY
ENZYME SPECIFICITY
STEREOSPECIFICITY
SUBSTRATE SPECIFICITY
REACTION SPECIFICITY

18. ENZYME SPECIFICITY SUBSTRATE SPECIFICITY REACTION SPECIFICITY
STEREOSPECIFICITY
ENZYMES SHOW SPECIFICITIES ONLY WITH A SPECIFIC GROUP OF A SUBSTRATE
(e.g. urease catalyses the hydrolysis of urea)
ENZYMES CATALYZE SIMILAR TYPE OF REACTION BUT DIFFER IN THEIR ACTION DUE TO SUBSTRATE SPECIFICITY
Example:
Pepsin hydrolysis – peptide bond
(phenyl alanine & tyrosine)
b. Trypsin (peptide bond – arginine or lysin)
SUBSTRATE
SPECIFICITY
A SUBSTRATE CAN UNDERGO MANY REACTIONS BUT IN REACTION SPECIFICITY, ONE ENZYME – CATALYZE ONE REACTION
(Example: OXALIC ACID – catalyze by separate enzymes)
REACTION SPECIFICITY

19. SUBSTRATE SPECIFICITY
ENZYME SPECIFICITY
STEREOSPECIFICITY
REACTION SPECIFICITY
SUBSTRATE SPECIFICITY

20. Explain mechanism of enzyme action
Learning Objectives
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

21. MECHANISM OF ENZYME ACTION
Combines w/ substrate P E
E : Enzyme molecule P : Product
S : Substrate molecule E : Enzyme
ES : Enzyme-Substrate

22. MECHANISM OF ENZYME ACTIONP E
Active Site/Catalytic Site : The site at which a substrate can meet with enzyme. It is made up of several amino acid.

23. Learning Objectives
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

24. FACTORS AFFECTING ENZYME ACTIVITY
SUBSTRATE CONCENTRATION
Low substrate concentration, the enzyme is not saturated
2. ENZYME CONCENTRATION
The rate of enzyme catalyzed reaction is directly proportional to the concentration of the enzyme.

25. FACTORS AFFECTING ENZYME ACTIVITY
3. EFFECT OF pH
Excessive changes in pH  completely denature and inactive enzymes
Optimum pH: enzyme activity is maximum at a particular pH.

26. FACTORS AFFECTING ENZYME ACTIVITY
4. EFFECT OF TEMPERATURE:
The velocity of enzyme reaction increases when temperature of the medium is increased  denatured by heat & becomes inactive.
Optimum temperature: the temperature at which maximum amount of substrate is converted to the product per unit time

27. FACTORS AFFECTING ENZYME ACTIVITY
5. EFFECT OF TIME : The time required for completion of an enzyme reaction increases with decrease in temperature from its optimum.
6. ENZYME INHIBITION
Inhibitors – chemical substances which inactivate the enzymes.
Inhibitors, e.g. Poisons (harmful)

28. Describe and classify coenzymes
Learning Objectives
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

29. CO-ENZYMES Loosely bound Removed by dialysis
Low molecular weight
Non-protein organic compound
Heat resistant
Function as co substances
Loosely bound
Removed by dialysis
Tightly bound – prosthetic group of enzyme
Water soluble vitamins: Vit. B complex & Vit. C (co-enzymes)

30. refers to the protein part of enzyme
CO-ENZYMES
CONJUGATED PROTEIN ENZYME = PROTEIN + PROSTHETIC GROUP
HOLOENZYME = APO-ENZYME + CO-ENZYME
PROTEIN PART + NON-PROTEIN PART (PROSTHETIC GROUP)
APO-ENZYME:
refers to the protein part of enzyme

31. CLASSIFICATION OF CO-ENZYMES
CO-ENZYMES FOR GROUP TRANSFER OF GROUPS OTHER THAN H
CO-ENZYMES FOR TRANSFER OF H
ATP and its relatives
CoA
B6 phosphate
Cobalamine (B12) co-enzyme
Biotin
Lipoic acid
Thiamine
Sugar phosphates
Folate co-enzymes
NAD, NADP
FAD
LIPOIC ACID
CO-ENZYME Q

32. Learning Objectives List the diagnostic value of plasma enzymes
Explain the role of enzymes as biological catalyst
State the general properties of enzymes
Classify enzymes
Explain enzyme specificity
Explain mechanism of enzyme action
State the factors that affect the rate of enzyme catalyzed
Describe and classify coenzymes
List the diagnostic value of plasma enzymes

33. Sr. ENZYMES INCREASED IN1
AMYLASE
Acute Pancreatitis 2
ACID PHOSPHATASE (pH=5)
Prostatic carcinoma 3
ALKALINE PHOSPHATASE (pH=10)
Liver disease, rickets 4
ASPARTATE TRANSAMINASE (AST)
Myocardial Infarction 5
ALANINE TRANSAMINASE (ALT)
Liver disease (liver cell damage) 6
LACTATE DEHYDROGENASE (LDH) 7
CREATINE KINASE (CK)
Myocardial Infarction and Skeletal Muscle disease 8
GLUTAMYL TRANSFERASE
Liver disease, biliary obstruction and alcoholism

34. Any Question???