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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).
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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
Reactions can be exergonic, yet slow- they require activation energy
Lowering the activation energy makes enzyme-catalyzed reactions faster
THE 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
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
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 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 40 0 20 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 2 3 6 7 9 10 0 1 4 5 8 pH Optimal pH for two enzymes
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.
b - galactosidase 10
b - galactosidase H O 2 galactose lactose b - galactosidase glucose (aka lactase in humans) 11