Back
Problem 10
What do we mean when we say an enzyme is saturated with substrate? When an enzyme is saturated with substrate, how does adding more (a) substrate and (b) enzyme affect the rate of the reaction?
Problem 19.14
What kind of reaction product might be a competitive inhibitor for the enzyme that catalyzes its formation?
Problem 19.16
Which type of enzyme regulation is best for the following situations?
a. An enzyme that becomes overactive during a disease
b. An enzyme needed only when there is low blood glucose
c. An enzyme that springs into action when a traumatic injury occurs
d. An enzyme needed only during adolescence
Problem 19.25
Answer questions (a)–(e) concerning the following reaction:
<IMAGE>
b. Since hydrogens are removed, the enzyme belongs to what subclass of the enzyme class from part (a)?
Problem 19.25
Answer questions (a)–(e) concerning the following reaction:
<IMAGE>
c. What is the substrate for the reaction as written?
Problem 19.25
"Answer questions (a)–(e) concerning the following reaction:
<IMAGE>
d. What is the product for the reaction as written?
Problem 19.25
Answer questions (a)–(e) concerning the following reaction:
<IMAGE>
a. The enzyme involved in this reaction belongs to what class of enzymes?
Problem 19.28
Explain how the following changes affect the rate of an enzyme-catalyzed reaction in the presence of an uncompetitive inhibitor:
(a) increasing the substrate concentration at a constant inhibitor concentration
Problem 19.28
Explain how the following changes affect the rate of an enzyme-catalyzed reaction in the presence of an uncompetitive inhibitor:
(b) decreasing the inhibitor concentration at a constant substrate concentration.
Problem 19.29
Explain how the following mechanisms regulate enzyme activity.
b. Genetic control
Problem 19.3
What type of enzyme regulation occurs in the following situations?
d. Conversion of isocitrate to α-ketoglutarate is inhibited by high levels of ATP. (Hint: ATP is neither a product nor a substrate in this reaction.)
Problem 19.36
What general kinds of reactions do the following types of enzymes catalyze?
b. Decarboxylases
Problem 19.36
What general kinds of reactions do the following types of enzymes catalyze?
c. Lipases
Problem 19.38
Name an enzyme that acts on each molecule.
a. Amylose
Problem 19.4
Describe the reactions that you would expect these enzymes to catalyze.
b. Aspartate transaminase
Problem 19.5
Name the enzyme whose substrate is
a. Urea
Problem 19.56
What general effects would you expect the following changes to have on the rate of an enzyme-catalyzed reaction for an enzyme that has its maximum activity at body temperature (about 37°C)?
a. Raising the temperature from 37°C to 70°C
Problem 19.56
What general effects would you expect the following changes to have on the rate of an enzyme-catalyzed reaction for an enzyme that has its maximum activity at body temperature (about 37°C)?
c. Adding an organic solvent, such as methanol
Problem 19.57
What general effects would you expect the following changes to have on the rate of an enzyme-catalyzed reaction for an enzyme that has its maximum activity at body temperature (about 37°C)?
c. Adding an oxidizing agent, such as hydrogen peroxide
Problem 19.58
The text discusses three forms of enzyme inhibition: uncompetitive inhibition, competitive inhibition, and irreversible inhibition.
b. What kinds of bonds are formed between an enzyme and each of these three kinds of inhibitors?
Problem 19.59
What kind of inhibition (uncompetitive, competitive, or irreversible) is present in each of the following:
a. Penicillin is used to treat certain bacterial infections. Penicillin is effective because it binds to the enzyme glycopeptide transpeptidase and does not dissociate.
Problem 19.59
What kind of inhibition (uncompetitive, competitive, or irreversible) is present in each of the following:
c. The antibiotic deoxycycline inhibits the bacterial enzyme collagenase, slowing bacterial growth. Deoxycycline does not fit into the active site of collagenase and binds elsewhere on the enzyme.
Problem 19.63
One mechanism by which lead exerts its poisonous effect on enzymes can be stopped by chelation therapy with EDTA. Describe this type of lead poisoning and explain why it is reversible.
Problem 19.64
The meat tenderizer used in cooking is primarily papain, a protease enzyme isolated from the fruit of the papaya tree. Why do you suppose papain is so effective at tenderizing meat?
Problem 19.66
Why do allosteric enzymes have two types of binding sites?
Problem 19.7
Identify and describe the chemical change in the lyase-catalyzed reaction in Table 19.4 that involves fumarate and malate. Identify the substrate(s) and product(s). <IMAGE>
Problem 19.8
Which of the following reactions can be catalyzed by a decarboxylase?
a. <IMAGE>
b. <IMAGE>
Problem 19.83
How can you distinguish between a competitive inhibitor and an uncompetitive inhibitor experimentally?
Problem 19.86
How will changing the conditions in an enzymatic reaction affect the rate of that reaction? Explain why in each case.
f. Decreasing the amount of substrate by half
Problem 19.87
Why are irreversible enzyme inhibitors referred to as poisons?
