1. They make things, they break things
Enzymes
They make things, they break things

2. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

3. What is an Enzyme? Most enzymes are globular proteins
Definition: “A macromolecule serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction”.
An RNase

4. Simulation: Observing an enzyme in action
18 volunteers (2 from each group)
Chemical reaction simulation

5. Simulation:
Test Reaction:

6. Method:

7. Enzyme Observations:

8. Enzymes: Not used up in the reaction.
Make the reaction require less energy.
One enzyme molecule can be a catalyst for several reactions.
Usually end in the suffix “-ase”. E.g. DNA polymerase, ATP synthase, Ligase, Sucrase, RNase, etc.
The FUNCTION of an enzyme is often indicated by the enzyme name.

9. Rate of Reaction:
What would happen to the rate of reaction if more substrate was added?
What would happen to the rate of reaction if more enzyme was added?

10. Why Enzymes? Energy required for RXN to occur.
Energy required for RXN to occur IF enzymes used.
HEAT

11. Why Enzymes? Enzymes lower the required Energy of Activation
This allows for faster reactions
This facilitates reactions that otherwise could not occur as quickly
Some enzymes can make reactions go trillions of times faster
Carbonic anhydrase (stomach) can catalyze over 1,000,000 reactions per second
Some enzymes are temperature/pH specific.

12. A B C D
Transition state A B EA C D
Free energy
Substrate A B
∆G < O C D
Products
Progress of the reaction

13. Progress of the reaction
Course of
reaction
without
enzyme
EA without
enzyme
EA with
enzyme
is lower
Substrate
Free energy
∆G is unaffected
by enzyme
Course of
reaction
with enzyme
Products
Progress of the reaction

14. How Do Enzymes Work?

15. How Do Enzymes Work? Orienteer: Stressor: Good microenvironment:
Active site encourages substrates to come together in the correct orientation
Stressor:
Induced fit stresses and bends critical chemical bonds.
Good microenvironment:
E.g. Active site is low pH.
Direct contribution:
Brief covalent bonds between substrate and R groups.

16. Substrate
Active site
Enzyme
Enzyme-substrate
complex
(a)
(b)

17. Sucrose + H2O + Sucrase  Sucrase-Sucrose-H2O Complex  Glucose + Fructose + Sucrase

18. Substrates enter active site; enzyme
changes shape such that its active site
enfolds the substrates (induced fit). 1
Substrates held in
active site by weak
interactions, such as
hydrogen bonds and
ionic bonds. 2
Substrate
Enzyme-substrate
complex
Active site can lower EA
and speed up a reaction. 3
Active
site is
available
for two new
substrate
molecules. 6
Enzyme 5
Products are
released.
Substrates are
converted to
products. 4
Products

20. Specificity Enzymes often catalyze only a single reaction
Enzymes are typically very specific
How many different kinds of enzymes are in the human body?

21. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

22. Minute Paper
What are the top three things you learned about enzyme function?

23. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

24. Enzyme Inhibition Enzymes can be inhibited by compounds
Inhibitor often similar in structure to substrate
Enzymes can be inhibited at active site or a different part of the molecule
Allosteric inhibition

25. Enzyme Inhibition Substrate Competitive inhibitor Enzyme
Noncompetitive inhibitor
(a) Normal binding
(b) Competitive
inhibition
(c) Noncompetitive
inhibition

26. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

27. Product Inhibition Simulation:
- Within each group, designate THREE people as enzymes (foldase1, foldase2, foldase3) and one person as a process. - Team up with two other groups. This gives us three teams. - Each team will have nine enzymes and three people capable of conducting a process.

28. First Enzyme: foldase1

29. Second Enzyme: foldase2

30. Third Enzyme: foldase3

31. Completed Airplanes:
MUST be IMMEDIATELY returned to foldase1 who must hold them ready for launch.
foldase1 must hold completed airplanes on the back of the hand between fingers.

32. Completed Airplanes:
foldase1 can only hold 8 airplanes (physical maximum)
foldase1 may continue its job if able.

33. Process:
Only ONE process per TEAM can be active at a time unless otherwise specified (take turns).
Process uses up completed paper airplanes by taking a completed airplane from a Foldase1 and launching it.
The TEAM that manufactures the most airplanes in 4 minutes wins!

34. What… …was the substrate? …was the product?
…is the name for foldase2 when it was folding an airplane?
…kind of inhibition occurred?
…was an active site?
…was an allosteric site?
…would need to occur so that more airplanes could be made by the foldase enzymes?

35. Product Feedback Inhibition
First enzyme in a biosynthesis pathway is(often) an allosteric enzyme
Multiple binding sites
Binding to effector changes conformation

36. Product Feedback Inhibition

37. Product Feedback Inhibition
Start of
pathway X
Inter-
mediate
Inter-
mediate
Product
Enzyme 1
Enzyme 2
Enzyme 3
Presence of product inhibits enzyme 1

38. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

39. Activators

40. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

41. Cofactors Non-protein chemical required for activity of enzymes
Many vitamins are cofactors
E.g., Iron, Manganese, Zinc
Cofactor functions
Assist with chemical reaction
Mg2+ and Taq
Allow protein to fold
E.g., zinc fingers

42. Enzymes:
Function
Inhibition
Product Inhibition
Activators
Cofactors

43. Enzymes and Energy

44. Enzymes and Energy

45. Enzymes in Action: Luciferase
Enzyme that oxidizes a substrate to form light
luciferin + O2 → oxyluciferin + light
Utilized by multiple organisms
Fishes, fungi, copepoda, shrimps, algæ, and more

46. Uses of Luciferase
Reporter genes
Various assays
Forensics

47. Video Clip http://www.youtube.com/watch?v=UXl8F-eIoiM
Short
Long