Title: Chymosin Lab
1Chymosin Lab
2- 1. Which variables influence enzyme performance
in general? - 2. With these variables in mind, hypothesize
What are the optimal conditions for the
performance of chymosin? (Hint you might
investigate the normal conditions under which
substances like chymosin are active). - 3. Briefly describe an investigation aimed at
optimizing one variable in chymosin Performance.
3Milk contains casein
- Casein- German, Kase cheese
- Casein is an emulsifying protein
- It is also a storage protein
- Structurally similar to gluten (found in grains)
4Cheese is made from curdled milk
- Rennet is added from the 4th stomach of a calf
- Rennet contains chymosin
- Chymosin is an enzyme which cuts casein
5ENZYMES
- They are protein catalysts
- They speed up reactions inside cells
- They are incredibly specific
- They are incredibly efficient
- -ase enzyme
6Chymosin is a protease
- A protease is an enzyme which cuts proteins
- Specifically, it is an aspartate protease
- Has an aspartate residue at its active site
- HIV-Protease 1 is also an aspartate protease
7Enzymes make it easier for reactions to happen
8Reactions can be exergonic, yet slow- they
require activation energy
9Lowering the activation energy makes
enzyme-catalyzed reactions faster
10THE REACTION DIAGRAM Enzymes can dramatically
lower the energy of activation for a reaction
no enzyme
with enzyme
E
a
E
Energy
a
reactants
products
Reaction Course
Note that the equilibrium of the reaction is
unaffected
12
11The stages of enzyme catalysis
- Substrate(s) binding
- Reaction of substrate to form product(s)
- Release of products
- The enzyme is ready to bind the next substrate
- Enzymes are unchanged by the reactions they
catalyze
12Enzyme Inhibition- Enzymes can be sped up or
slowed down
13Protease inhibitors make enticing HIV drug
candidates
14Effects of Temperature and pH
- Each enzyme has an optimal temperature in which
it can function - Each enzyme has an optimal pH in which it can
function - Tertiary structure can be radically altered by
changes in pH
15Optimal temperature for typical human enzyme
Optimal temperature for enzyme of thermophilic
(heat-tolerant
bacteria)
Different enzymes work optimally at different pHs
and temper-atures
Rate of reaction
0
20
40
60
80
100
Temperature (C)
Optimal temperature for two enzymes
Optimal pH for pepsin (stomach enzyme)
Optimal pH for trypsin (intestinal enzyme)
Rate of reaction
0
1
2
3
4
5
6
7
8
9
10
pH
Optimal pH for two enzymes
16- 1. Which variables influence enzyme performance
in general? - 2. With these variables in mind, hypothesize
What are the optimal conditions for the
performance of chymosin? (Hint you might
investigate the normal conditions under which
substances like chymosin are active). - 3. Briefly describe an investigation aimed at
optimizing one variable in chymosin Performance.
17b
-
galactosidase
10
18b
-
galactosidase
H
O
2
galactose
lactose
b
-
galactosidase
glucose
(aka lactase in humans)
11