Question 1

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: A type of catalysis where the proton donor is not water.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 2

How can covalent modification be used to determine the mechanism of action of an enzyme?

Accepted Answer

If a particular amino acid side chain is

Question 3

Why are substrate analogs used to monitor enzyme activity?

Accepted Answer

Enzyme assays must be designed so that t

Question 4

In what type of inhibition can the inhibitor only bind to the ES complex to form an ESI complex?

Accepted Answer

A)  competitive 
B)  noncompetitive 
C)  irreversible 
D)  uncompetitive 
E)  None of the above. 
A)  competitive 
B)  noncompetitive 
C)  irreversible 
D)  uncompetitive 
E)  None of the above.

Question 5

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: An enzyme that temporarily undergoes covalent catalysis as part of its mechanism.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 6

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The inhibitor which binds only to the ES complex and lowers the Vmax and KM.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 7

The mechanism of chymotrypsin involves the formation of an unstable ________________-shaped intermediate that is stabilized by the oxyanion hole.

Accepted Answer

The answer of The mechanism of chymotrypsin involves the formation...

Question 8

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The enzyme inhibition that can be overcome by increasing the concentration of substrate.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 9

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The type of reaction catalyzed by proteases.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 10

Which type(s) of inhibition can be reversed?

Accepted Answer

A)  competitive 
B)  noncompetitive 
C)  uncompetitive 
D)  All of the above. 
E)  None of the above. 
A)  competitive 
B)  noncompetitive 
C)  uncompetitive 
D)  All of the above. 
E)  None of the above.

Question 11

You measure the initial velocity of an enzyme in the absence and presence of an inhibitor.  In each case the inhibitor is at 10 µM.  Show the primary data for all three cases and the Lineweaver–Burk plot.  Calculate the KM and Vmax for each case both graphically and mathematically.  Determine the mechanism for each inhibitor and where they will interact on the enzyme.
$\begin{array}{c}
\underline{\text { Initial Velocity ( } \mu \mathrm { mole } / \mathrm { ml } \mathrm { min } )}\
\begin{array} { c c c c } 
 [ \mathrm { S } ] \mathrm { mM } & \begin{array} { c } 
\text { Enzyme } \
\text { alone }
\end{array} & \begin{array} { c } 
\text { Enzyme } \
+ \text { inhibitor 1 }
\end{array} & \begin{array} { c } 
\text { Enzyme } \
+ \text { inhibitor 2 }
\end{array} \
0.33 & 1.65 & 1.05 & 0.79 \
0.50 & 2.13 & 1.43 & 1.02 \
1.00 & 2.99 & 2.22 & 1.43 \
2.00 & 3.72 & 3.08 & 1.79 \
5.00 & 4.00 & 3.80 & 2.00
\end{array}
\end{array}$

Accepted Answer

Construct a double-reciprocal

Question 12

An uncompetitive inhibitor will have two ________________ lines on a double-reciprocal plot.

Accepted Answer

The answer of An uncompetitive inhibitor will have two ________________...

Question 13

An enzyme catalyst mechanism that uses a metal cation to stabilize a negative charge in the active site is ________________.

Accepted Answer

The answer of An enzyme catalyst mechanism that uses a...

Question 14

Draw and describe the reaction pathway for a noncompetitive inhibitor.

Accepted Answer

The figure should resemble the reaction

Question 15

Which amino acids in chymotrypsin are found in the active site and are participants in substrate cleavage?

Accepted Answer

A)  his, ser, asp 
B)  his, ser 
C)  asp, lys 
D)  lys, arg 
E)  his, ser, arg 
A)  his, ser, asp 
B)  his, ser 
C)  asp, lys 
D)  lys, arg 
E)  his, ser, arg

Question 16

Bacteria that become penicillin resistant express an enzyme called β-lactamase and this enzyme hydrolyses the lactam ring on penicillin.  Suggest a reason why this protein allows cells to grow in the presence of penicillin.

Accepted Answer

Penicillin is a suicide inhibitor of the

Question 17

Describe the mechanism for the proteolysis catalyzed by chymotrypsin.

Accepted Answer

This is an acid-base, covalent catalysis

Question 18

Binding of a water molecule to the zinc ion induces:

Accepted Answer

A)  a hydronium ion to form. 
B)  a large conformation change in the binding site. 
C)  ionization of a his residue, which functions as a strong nucleophile. 
D)  a lowered pKa for water, which leads to the formation of a zinc-bound hydroxide ion. 
E)  an altered KM value. 
A)  a hydronium ion to form. 
B)  a large conformation change in the binding site. 
C)  ionization of a his residue, which functions as a strong nucleophile. 
D)  a lowered pKa for water, which leads to the formation of a zinc-bound hydroxide ion. 
E)  an altered KM value.

Question 19

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: An enzyme that is part of a pigment formation pathway and has a low optimum temperature.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Question 20

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The type of catalysis in which two substrates are brought into close proximity.

Accepted Answer

A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive 
A) hydrolysis 
B) affinity label 
C) tyrosinase 
D) chymotrypsin 
E) pepsin
F)noncompetitive
G)uncompetitive
H)heterotropic
I)approximation and orientation
J)acid-base
K)competitive

Exam 8: Mechanisms and Inhibitors

Choose the correct answer from the list below. Not all of the answers will be used. -____________: A type of catalysis where the proton donor is not water.

How can covalent modification be used to determine the mechanism of action of an enzyme?

Why are substrate analogs used to monitor enzyme activity?

In what type of inhibition can the inhibitor only bind to the ES complex to form an ESI complex?

Choose the correct answer from the list below. Not all of the answers will be used. -____________: An enzyme that temporarily undergoes covalent catalysis as part of its mechanism.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The inhibitor which binds only to the ES complex and lowers the Vmax and KM.

The mechanism of chymotrypsin involves the formation of an unstable ________________-shaped intermediate that is stabilized by the oxyanion hole.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The enzyme inhibition that can be overcome by increasing the concentration of substrate.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The type of reaction catalyzed by proteases.

Which type(s) of inhibition can be reversed?

An uncompetitive inhibitor will have two ________________ lines on a double-reciprocal plot.

An enzyme catalyst mechanism that uses a metal cation to stabilize a negative charge in the active site is ________________.

Draw and describe the reaction pathway for a noncompetitive inhibitor.

Which amino acids in chymotrypsin are found in the active site and are participants in substrate cleavage?

Bacteria that become penicillin resistant express an enzyme called β-lactamase and this enzyme hydrolyses the lactam ring on penicillin. Suggest a reason why this protein allows cells to grow in the presence of penicillin.

Describe the mechanism for the proteolysis catalyzed by chymotrypsin.

Binding of a water molecule to the zinc ion induces:

Choose the correct answer from the list below. Not all of the answers will be used. -____________: An enzyme that is part of a pigment formation pathway and has a low optimum temperature.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The type of catalysis in which two substrates are brought into close proximity.

Biochemistry and the Unity of Life

Water, Weak Bonds, and the Generation of Order Out of Chaos

Amino Acids

Protein Three-Dimensional Structure

Techniques in Protein Biochemistry

Basic Concepts of Enzyme Action

Kinetics and Regulation

Hemoglobin: an Allosteric Protein

Carbohydrates

Lipids

Membrane Structure and Function

Signal Transduction Pathways

Digestion: Turning a Meal Into Cellular Biochemicals

Metabolism: Basic Concepts and Design

Glycolysis

Gluconeogenesis

Preparation for the Cycle

Harvesting Electrons From the Cycle

The Electron Transport Chain

The Proton-Motive Force

The Light Reactions

The Calvin Cycle

Glycogen Degradation

Glycogen Synthesis

The Pentose Phosphate Pathway

Fatty Acid Degredation

Fatty Acid Synthesis

Lipid Synthesis

Amino Acid Degradation and the Urea Cycle

Amino Acids Synthesis

Nucleotide Metabolism

The Structure of Informational Macromolecules: Dna and Rna

DNA Replication

DNA Repair and Recombination

RNA Synthesis and Regulation in Prokaryotes

Gene Expression in Eukaryotes

RNA Processing in Eukaryotes

The Genetic Code

The Mechanism of Protein Synthesis

Recombinant DNA Techniques

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