AP Lab 2: Enzyme Catalysis

1
What do enzymes do?

• Enzymes are proteins that
• Speed up chemical reactions
• Are re-useable
• Lower the activation energy required!
• Act like a lock and key (specificity!)

R
P
http//www.people.virginia.edu/rjh9u/gif/actenz.g
if
2
Lock and Key Model
E-S Complex
Active site
http//www.celltech.com/resources/vt/images/lockke
y.gif
3
Reaction of Interest

• We are interested in the following reaction

catalase
2 H2O2 2 H2O O2 (gas)

• Hydrogen peroxide is a harmful cellular
  metabolic by-product.
• Catalases substrate is hydrogen peroxide.
• Is catalase an anabolic or catabolic enzyme?

4
How we measure reaction rate

• Combine enzyme and substrate what happens to the
  disk as the reaction proceeds?
• Why?

5
Factors that influence enzymes and reaction rates

• Temperature
• pH
• Salinity
• Concentration of enzyme and substrate
• How do you think these factors affect enzymes and
  their reactions?

6
Post-Lab Discussion

• Describe
  the graph
• Enzyme

http//www.soton.ac.uk/plf/ScI-Journal/vol1no2/en
zyme5.gif
7
Post-Lab Discussion

• Describe
  the graph
• Substrate

http//www.soton.ac.uk/plf/ScI-Journal/vol1no2htt
p//www.science.siu.edu/microbiology/micr425/425No
tes/Image108.gif/enzyme5.gif
8
Post-Lab Discussion

• Describe
  the graph
• Temperature
• Collision rate
• Denaturation

9
What is denaturation?

• What is it?
• When does it happen?

http//www.sp.uconn.edu/bi107vc/images/mol/denatu
ration.gif
http//protein.mchem.washington.edu/downloads/ub/
10
Oxygen Gas?

• What are tests for oxygen gas?

11
Post-Lab Discussion

• Describe
  the graph
• pH

12
Other factors affecting enzyme rates of reaction
e
INDUCED FIT MODEL!!
13
Other factors affecting enzyme rates of reaction
14
Inhibitor Mechanism