1. What Are Enzymes? An enzyme is a catalyst in cellular reactions.
DEFINE catalyst
Enzymes are protein or nucleic acids with (tertiary and quaternary structure).

2. Enzymes have specificity Are reusable End in -ase -Sucrase -Lactase
-Maltase

3. Parts of a chemical reaction:
Chemical reactions control all of the chemical compounds in our body allowing us to move, grow, react, and even reproduce.
Parts of a chemical reaction:
The sum of all of the chemical reactions that occur in our bodies is called metabolism.
Reactants > Products

4. Catabolism
Chemical reactions in which molecules are broken done and release energy; degradation
Example: Hydrolysis

5. Anabolism
Chemical reactions in which molecules are assembled, usually they require energy; synthesis
Example: Dehydration Synthesis

6. catabolism + anabolism = metabolism
the sum of all chemical reactions with a living organism
catabolism + anabolism = metabolism

7. What is lactose intolerance then?
Why do we need enzymes?
ENZYMES!
Reactants > Products
Enzymes catalyze the chemical reactions in our body
What is lactose intolerance then?

8. How do enzymes work? The Enzyme-Substrate Complex
Each enzyme has a unique 3-D shape, including a surface groove called an active site.
The enzyme works by binding a specific chemical reactant (substrate) to its active site, causing the substrate to become unstable and react.
The resulting product is then released from the active site.

9. How Do Enzymes Work?
Enzymes work by weakening bonds which lowers activation energy.

10. Active Site
Active Site
Enzyme
Substrate

11. Shape of a Protein ...Structure Meets Function
An enzyme fits with its substrate like a ____ and ____.
Enzyme have specificity.

12. 4 levels of Protein Structure

13. How important is the shape of an enzyme?
Which substrate would be catalyzed by this enzyme?

14. How Do You Stop an Enzyme?
Denaturation:
• The process of changing the shape of a enzyme thus destroying its function
•Caused by heat or pH
Irreversible egg protein denaturation caused by high temperature (while cooking it).

15. Factors Affecting Enzyme Activity
Temperature pH
Cofactors & Coenzymes
Inhibitors

16. Coenzymes & Cofactors
Non-protein substances (zinc, iron, copper, vitamins) are sometimes needed for proper enzymatic activity.
Example of enzyme cofactor : Ribbon-diagram showing carbonic anhydrase II. The grey sphere is the zinc cofactor in the active site.

17. Catecholase Catecholase is present in most fruits and vegetables.
It is the enzyme that facilitates the browning of cut or bruised fruits and vegetables by catalyzing the following reaction:
(catecholase)
catechol oxygen  polyphenol
colorless substrate brown product

18. So what happened to the apple slice?
Lemon juice and other acids are
used to preserve color in fruit,
particularly apples, by lowering the pH
and removing the copper site (cofactor)
necessary for the enzyme to function.
catecholase
catechol O  polyphenol
colorless substrate brown product
So what happens to catecholase when you add an acid (lemon juice) to the apple slice?

19. Two Types of Enzyme Inhibitors
1. Competitive inhibitors:
Chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.
Example: Methotrexate is used in chemotherapy and inhibits an enzyme involved in DNA replication (a process necessary for cell division)
Substrate

20. Two Types of Enzyme Inhibitors
Noncompetitive inhibitors:
Do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, altering the active site.
Substrate
active
site altered

21. Enzyme Inhibitors
Blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance.
Many drugs are enzyme inhibitors.
Enzymes are also used as pesticides and herbicides.

22. Overview of Mammalian Digestive Enzymes