1. ENZYME CATALYSIS LAB
AP Lab #1/ AP Biology

2. Pre lab notebook work due tomorrow
See rubric for expectations
I will collect a PRINTED copy of your “pre-lab notebook” while you take the prelab quiz
I will grade your work to make sure things are complete.

3. FIRST….
Let’s review enzymes!

4. http://www.stolaf.edu/people/giannini/flashanima t/enzymes/transition%20state.swf

6. Binding Specificity
Even when different substrate molecules are present, only those that have the specific shape complementary to the active site are able to bind with the enzyme's active site.

8. INDUCE FIT Once substrate binds…
Active site undergoes conformational change (changes shape)
enhances catalysis  speeds up substrate to product conversion b/c allows bonds to break/be made more quickly

9. ENZYMES ARE RECYCLED
Release of products restores enzyme to its ORIGINAL conformation (shape)
Enzyme can repeat this reaction over and over, as long as substrate molecules are present

10. WHAT FACTORS DENATURE PROTEINS?pH
Salt concentration
Temperature
Substrate or enzyme [ ]
WHAT OTHER FACTORS AFFECT ENZYME RATE?

11. Lab #1: Enzyme Catalysis
INTRODUCTION TO … AP
Lab #1: Enzyme Catalysis

12. CONCEPTS You need to change the rate of reactivity
Understand substrates and products, enzyme structure & denaturation
Measure factors affecting enzyme activity
Measure rate of O2 production
Experimental design- PART 2
You need to change the rate of reactivity
Either increase or decrease the rate BUT the rate CAN’T be zero.

13. What is are the reactants (substrate) & products?
KEY CONCEPTS
What is are the reactants (substrate) & products?
What enzyme are we using?
H2O2  H2O + O2
Hydrogen water + oxygen gas
peroxide
catalase

14. NOTE: Oxygen gas(O2) forms BUBBLES
ENZYME
SUBSTRATE (REACTANT)
PRODUCTS

15. WHY DOES H2O2 NEED TO BE BROKEN DOWN?
H2O2 is poisonous (TOXIC) to cells; water and O2 are NOT
H2O2 is naturally produced as a byproduct of oxygen metabolism (ex: cellular respiration)
Almost all organisms possess enzymes known collectively as PEROXIDASES (ex: catalase).
Converts H2O2 into harmless H2O and O2

16. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.
NOTE: The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.

17. http://www.explorebiology.com/images/enzyme- apparatus.gif
H2O

18. Vial filled with catalase, H2O2 and variable (PART 2 only)
Graduated cylinder

20. Calculate the RATE OF ENZYMATIC REACTION
ANALYSIS OF DATA
Calculate the RATE OF ENZYMATIC REACTION

21. SOME REAL-LIFE APPLICATIONS FOR THIS LAB….
Bacterial enzymes and use of disinfectants
Many disinfectants, such as chlorine, iodine, iodophores, mercurials, silver nitrate, formaldehyde, and ethylene oxide, INACTIVATE bacterial enzymes and block metabolism.
Extremes of temperature to control bacteria.
High temperatures, such as autoclaving, boiling, and pasteurization denature proteins and STOP functions
Cold temperatures, such as refrigeration or freezing, SLOW DOWN or STOP enzyme rxns