Question 1

A noncompetitive inhibitor can bind to either the enzyme or the enzyme-substrate complex.

Accepted Answer

A noncompetitive inhibitor can bind to either the enzyme or the enzyme-substrate complex, causing a change in the shape of the enzyme and hindering its ability to catalyze the reaction.

Question 2

Rational drug design involves the study of enzyme structure and the use of computers to generate structures of possible enzyme inhibitors.

Accepted Answer

Rational drug design is a process that involves the in-depth study of enzyme structure and function to design inhibitors specifically targeted towards them using computer-aided techniques.

Question 3

Both reversible and irreversible inhibitors can be separated from solutions of enzymes by dialysis.

Accepted Answer

Reversible inhibitors can be removed by dialysis as they bind non-covalently, while irreversible inhibitors form covalent bonds with the enzyme, making them inseparable by dialysis.

Question 4

The regulatory and active sites on an oligomeric enzyme can be on different subunits.

Accepted Answer

This is because oligomeric enzymes are formed by multiple subunits coming together to form a functional enzyme. Each subunit may have its own unique catalytic and regulatory sites, which can contribute to the overall activity of the enzyme.

Question 5

At sufficiently high substrate concentration all types of reversible inhibition can be overwhelmed. At high substrate concentration the enzyme will be saturated and the reaction will proceed at the same maximum velocity as in the absence of inhibitor.

Accepted Answer

At high substrate concentrations, competitive inhibitors can be overcome because they compete with the substrate for the active site, but non-competitive and uncompetitive inhibitors cannot be fully overcome by increasing substrate concentration, as they do not compete for the active site and affect the enzyme activity differently.

Question 6

Natural inhibitors often are regulators of metabolic reactions.

Accepted Answer

Natural inhibitors can regulate metabolic reactions by slowing down or stopping the enzymatic activity. Examples of natural inhibitors include allosteric inhibitors and feedback inhibitors.

Question 7

Select the correct class of enzyme for each of these reactions. A) isomerase
B) ligase
C) lyase
D) transferase
E) oxidoreductase
F) hydrolase
-Glucose-6-phosphate →
Fructose-6-phosphate

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 8

Increasing the concentration of a classic competitive inhibitor has no effect on the maximum velocity of an enzyme-substrate reaction.

Accepted Answer

A classic competitive inhibitor binds to the active site of an enzyme, preventing substrate molecules from binding. However, with increasing concentrations of the inhibitor, more substrate molecules can still bind to the enzyme and reach the maximum velocity. Therefore, the maximum velocity is not affected by competitive inhibition, and remains the same as in the absence of the inhibitor.

Question 9

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Polypeptide + H₂O → Amino acids

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 10

Very few catalytic proficiency values are known because many nonenzymatic reaction rates are so slow that they are difficult to measure.

Accepted Answer

This statement is true, since catalytic proficiency values are typically calculated by comparing the rate of a given enzymatic reaction to the rate of a closely related nonenzymatic reaction. However, many nonenzymatic reactions are so slow that it is difficult to accurately measure their rates, which limits the number of catalytic proficiency values that can be determined.

Question 11

In bi-substrate reactions the substrates always bind to the enzyme in a specific order.

Accepted Answer

In bi-substrate reactions, substrates can bind to the enzyme in a specific order (sequential mechanism) or bind in any order (random mechanism), depending on the enzyme's mechanism of action.

Question 12

The most common enzyme inhibitors are competitive inhibitors.

Accepted Answer

Competitive inhibitors bind to the active site of the enzyme and compete with the substrate, thereby reducing the rate of reaction. They are the most common type of enzyme inhibitors.

Question 13

All irreversible inhibitors known are from man-made sources.

Accepted Answer

Irreversible inhibitors can also occur naturally, such as in toxins and poisons produced by plants, animals, and microorganisms.

Question 14

Affinity labels are radioactive competitive inhibitors used to identify the most important residues in an enzymeʹs active site.

Accepted Answer

Affinity labels are not necessarily radioactive. They are chemical compounds that irreversibly bind to specific amino acid residues in an enzyme's active site, allowing the determination of which residues are essential for enzyme activity. Traditionally, affinity labeling does not involve the use of radioactive compounds.

Question 15

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Lactate + NAD⁺→ Pyruvate + NADH + H⁺

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 16

Select the correct class of enzyme for each of these reactions. A) isomerase
B) ligase
C) lyase
D) transferase
E) oxidoreductase
F) hydrolase
-L-aspartic acid +
a-ketoglutarate → oxaloacetic acid + L-Glutamate

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 17

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Pyruvate + H⁺→ Acetaldehyde + Carbon dioxide

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 18

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -L-Glutamate + ATP + NH₄⁺ → L-glutamine + ADP + P_i

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 19

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Sucrose + H₂O → Fructose + Glucose

Accepted Answer

The answer of Select the correct class of enzyme for...

Question 20

Allosteric modulators bind covalently to the regulatory site of an enzyme and change its conformation.

Accepted Answer

Allosteric modulators bind non-covalently to the regulatory site of an enzyme and change its conformation.

Quiz 5: Properties of Enzymes

A noncompetitive inhibitor can bind to either the enzyme or the enzyme-substrate complex.

Rational drug design involves the study of enzyme structure and the use of computers to generate structures of possible enzyme inhibitors.

Both reversible and irreversible inhibitors can be separated from solutions of enzymes by dialysis.

The regulatory and active sites on an oligomeric enzyme can be on different subunits.

At sufficiently high substrate concentration all types of reversible inhibition can be overwhelmed. At high substrate concentration the enzyme will be saturated and the reaction will proceed at the same maximum velocity as in the absence of inhibitor.

Natural inhibitors often are regulators of metabolic reactions.

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Glucose-6-phosphate → Fructose-6-phosphate

Increasing the concentration of a classic competitive inhibitor has no effect on the maximum velocity of an enzyme-substrate reaction.

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Polypeptide + H2O → Amino acids

Very few catalytic proficiency values are known because many nonenzymatic reaction rates are so slow that they are difficult to measure.

In bi-substrate reactions the substrates always bind to the enzyme in a specific order.

The most common enzyme inhibitors are competitive inhibitors.

All irreversible inhibitors known are from man-made sources.

Affinity labels are radioactive competitive inhibitors used to identify the most important residues in an enzymeʹs active site.

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Lactate + NAD+ → Pyruvate + NADH + H+

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -L-aspartic acid + a-ketoglutarate → oxaloacetic acid + L-Glutamate

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Pyruvate + H+ → Acetaldehyde + Carbon dioxide

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -L-Glutamate + ATP + NH4+ → L-glutamine + ADP + Pi

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Sucrose + H2O → Fructose + Glucose

Allosteric modulators bind covalently to the regulatory site of an enzyme and change its conformation.

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Polypeptide + H₂O → Amino acids

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Lactate + NAD⁺→ Pyruvate + NADH + H⁺

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Pyruvate + H⁺→ Acetaldehyde + Carbon dioxide

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -L-Glutamate + ATP + NH₄⁺ → L-glutamine + ADP + P_i

Select the correct class of enzyme for each of these reactions. A) isomerase B) ligase C) lyase D) transferase E) oxidoreductase F) hydrolase -Sucrose + H₂O → Fructose + Glucose