Chymosin Lab. 1. Which variables influence enzyme performance in general? 2. With these variables in...
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Transcript of Chymosin Lab. 1. Which variables influence enzyme performance in general? 2. With these variables in...
Chymosin Lab
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.
Milk contains casein
• Casein- German, Kase= cheese
• Casein is an emulsifying protein
• It is also a storage protein
• Structurally similar to gluten (found in grains)
Cheese 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
ENZYMES
• They are protein catalysts
• They speed up reactions inside cells
• They are incredibly specific
• They are incredibly efficient
• -ase = “enzyme”
Chymosin 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
Enzymes make it easier for reactions to happen
Reactions can be exergonic, yet slow- they require activation energy
Lowering the activation energy makes enzyme-catalyzed reactions faster
THE REACTION DIAGRAMEnzymes can dramatically lower the energy of activation for a reaction
Reaction Course
Energyreactants
products
E a
E a
no enzyme
with enzyme
12Note that the equilibrium of the reaction is unaffected
The 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
Enzyme Inhibition- Enzymes can be sped up or slowed down
Protease inhibitors make enticing HIV drug candidates
Effects 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
Optimal temperature fortypical human enzyme
Optimal temperature forenzyme of thermophilic (heat-tolerant bacteria)
Temperature (°C)
Optimal temperature for two enzymes
0 20 40 60 80 100
Rate
of r
eacti
onOptimal pH for pepsin(stomach enzyme)
Optimal pHfor trypsin(intestinalenzyme)
pH
Optimal pH for two enzymes
0
Rate
of r
eacti
on
1 2 3 4 5 6 7 8 9 10
Different enzymes work optimally at different pHs and temper-atures
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.
-galactosidase
10
-galactosidase
11
lactose
galactose
glucose
H2O
- galactosidase(aka lactase in humans)