Biochemistry 3: Enzymes (Part 2)

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What type of inhibitor binds to an allosteric site on the enzyme?

Competitive inhibitor

Uncompetitive inhibitor

Non-competitive inhibitor (correct)

Irreversible inhibitor

What happens to the observed KM and Vmax in non-competitive inhibition?

Both KM and Vmax are reduced (correct)

KM is decreased, Vmax is increased

KM is unaffected, Vmax is decreased

KM is increased, Vmax is decreased

What type of inhibition occurs when an inhibitor binds covalently to a residue within the active site of the enzyme?

Non-competitive inhibition

Competitive inhibition

Uncompetitive inhibition

Irreversible inhibition (correct)

What is the effect of a non-competitive inhibitor on the enzyme's activity?

It converts the enzyme to an inactive state Signup and view all the answers

Which type of inhibitor binds to the enzyme-substrate complex?

Uncompetitive inhibitor Signup and view all the answers

What is the effect of an inhibitor on the Lineweaver-Burk plot in non-competitive inhibition?

It decreases the slope and increases the intercept Signup and view all the answers

What is the characteristic of competitive inhibition in terms of substrate concentration?

Inhibition is overcome at high substrate concentration Signup and view all the answers

What is the main difference between competitive and non-competitive inhibitors?

Competitive inhibitors bind to the active site, while non-competitive inhibitors bind to an allosteric site. Signup and view all the answers

What type of inhibitor affects the enzyme's activity by binding to the active site?

Competitive inhibitor Signup and view all the answers

What is the effect of a competitive inhibitor on the Km and Vmax of an enzyme?

Km increases, Vmax remains the same. Signup and view all the answers

What is the purpose of product inhibition in enzyme-catalyzed reactions?

To slow down the reaction once enough product is made. Signup and view all the answers

What is the definition of Km?

The substrate concentration that produces half maximal velocity. Signup and view all the answers

What is the effect of increasing substrate concentration on competitive inhibition?

It overcomes the inhibition. Signup and view all the answers

What is the equation that describes the effect of a competitive inhibitor on the enzyme activity?

v0 = Vmax/(KM + [S] + Ki[I]). Signup and view all the answers

What is the purpose of enzymes in biological systems?

To increase the rate of reactions. Signup and view all the answers

What is an example of an enzyme that is inhibited by its product?

Galactase. Signup and view all the answers

What is the name of the enzyme composed of two different protein subunits?

LDH Signup and view all the answers

What is the location of the HHMM (LDH3) isozyme?

Unknown location Signup and view all the answers

Which isozyme is increased in leukemia?

All five isozymes Signup and view all the answers

What is the biomedical importance of enzymes?

They help in diagnosing diseases Signup and view all the answers

What is the principle of ELISA?

Linking an enzyme to an antibody Signup and view all the answers

What is the result of the immunological reaction between the antigen and the prepared antibody in ELISA?

The amount of antibody is proportional to the amount of antigen Signup and view all the answers

What is measured in the kinetics of an enzyme?

The rate of substrate conversion Signup and view all the answers

What is the effect of the inhibitor on the kinetics of an enzyme?

It decreases the Vmax Signup and view all the answers

What is the binding site of allosteric effectors?

A site different from the substrate binding pocket Signup and view all the answers

What is the effect of allosteric effectors on enzyme activity?

Increase enzyme activity Signup and view all the answers

What is the result of K-type regulation?

Decrease in KM Signup and view all the answers

What is the result of V-type regulation?

Increase in Vmax Signup and view all the answers

What is the characteristic of isoenzymes?

They catalyze the same reaction but differ in their physical properties Signup and view all the answers

How do isoenzymes differ from each other?

They differ in their amino acid sequence Signup and view all the answers

What is the characteristic of creatine kinase isoenzymes?

They are composed of two polypeptides (B and M subunits) Signup and view all the answers

What is the purpose of electrophoresis in isoenzyme analysis?

To separate isoenzymes based on their physical properties Signup and view all the answers

What is the value of Km in the presence of the inhibitor?

31 μM Signup and view all the answers

What is the type of inhibition depicted in the graph?

Competitive Signup and view all the answers

What is the purpose of the Lineweaver-Burk method?

To linearize the non-linear Michaelis-Menten equation Signup and view all the answers

How is enzyme activity regulated?

By gene expression, substrate and cosubstrate availability, pH, temperature, and allosteric regulators Signup and view all the answers