Enzyme Regulation: Allosteric Control and Covalent Modification

Play an AI-generated podcast conversation about this lesson

What is the term for the increase or decrease in binding affinity of other sites due to the binding of an effector molecule?

Cooperativity

Allosterism (correct)

Feedback inhibition

Homotropic regulation

What type of allosteric modulator is a substrate for its target enzyme?

Negative allosteric

Homotropic (correct)

Heterotropic

Positive allosteric

What is the term for the increase in binding affinity of other molecules due to the binding of one molecule?

Negative cooperativity

Positive cooperativity (correct)

Feedback inhibition

Allosterism

What is the term for the decrease in binding affinity of other molecules due to the binding of one molecule?

Negative cooperativity Signup and view all the answers

What type of allosteric modulator is not a substrate for its target enzyme?

Heterotropic Signup and view all the answers

What is the term for the regulation of an enzyme's activity by a substance that binds at a second site?

Allosteric regulation Signup and view all the answers

What is the term for a protein that has its biological activity affected by the binding of other substances?

Allosteric enzyme Signup and view all the answers

What is the term for the inhibition of an enzyme's activity by a substance that binds at a second site?

Negative allosterism Signup and view all the answers

What is the example of an enzyme that is regulated by both its substrate and other molecules?

Hemoglobin Signup and view all the answers

What is the term for the regulation of an enzyme's activity by a substrate?

Homotropic regulation Signup and view all the answers

What is the primary mechanism by which allosteric control regulates enzyme activity?

Conformational changes induced by effector binding Signup and view all the answers

What is the most common type of reversible covalent modification?

Phosphorylation Signup and view all the answers

What is the term for the process by which an enzyme is activated by cleavage of non-active protein?

Proteolytic activation Signup and view all the answers

What is the characteristic exhibited by allosteric enzymes?

Cooperativity Signup and view all the answers

What is the term for the binding of small molecules to an enzyme at sites other than the active site?

Allosteric control Signup and view all the answers

What is the result of effector binding to an allosteric enzyme?

Conformational changes in the enzyme Signup and view all the answers

What is the term for the changes that occur when a binding site of a protein or receptor is activated or deactivated?

Cooperativity Signup and view all the answers

What is the primary difference between allosteric and proteolytic activation?

Binding of small molecules vs. cleavage of non-active protein Signup and view all the answers

What is the term for the attachment of a phosphate group to a protein?

Phosphorylation Signup and view all the answers

What is the characteristic of allosteric enzymes that allows them to exhibit cooperativity?

Multiple binding sites Signup and view all the answers

What does the enzyme CTP synthetase catalyze?

The ATP-dependent transfer of the amide nitrogen from glutamine to the C-4 position of UTP Signup and view all the answers

What type of regulation is used by feedback inhibition?

Allosteric regulation Signup and view all the answers

What is the organization of the ATCase catalytic unit?

6 subunits organized into 2 trimers Signup and view all the answers

How many models are used to explain allosterism and cooperativity?

Two Signup and view all the answers

What is the name of the model proposed by Wyman, Monod, and Changeux in 1965?

The Concerted Model Signup and view all the answers

What is the main feature of the Sequential Model?

The binding of substrate induces a conformational change from the T form to the R form Signup and view all the answers

What is unique to the Sequential Model of behavior?

Negative cooperativity Signup and view all the answers

What is the main difference between the Concerted Model and the Sequential Model?

The Concerted Model has all subunits in the same conformation, while the Sequential Model has subunits in different conformations Signup and view all the answers

What is the induced-fit model of substrate binding?

A model where the enzyme is flexible and the active site reshapes to fit the substrate Signup and view all the answers

What is the function of allosteric activators in the Concerted Model?

To bind to and stabilize the R (active) form Signup and view all the answers

What is the principle behind the induced-fit protocol of substrate binding?

The active site adjusts to fit the substrate. Signup and view all the answers

What is the result of substrate binding to one subunit of an enzyme?

The binding sites of other subunits are more receptive to substrate. Signup and view all the answers

What is the purpose of phosphorylation in enzyme activity?

To activate or deactivate the enzyme. Signup and view all the answers

What is the term for the inactive precursor of an enzyme that is converted to its active form by proteolysis?

Proenzyme. Signup and view all the answers

What is the role of a coenzyme in an enzymatic reaction?

To take part in the reaction and be regenerated for further reaction. Signup and view all the answers

What is the function of NAD+ in redox reactions?

To accept electrons from the reaction. Signup and view all the answers

What is the effect of substrate binding to an enzyme on its activity?

It increases the activity of the enzyme. Signup and view all the answers

What is the term for the process of adding or removing a phosphate group from an enzyme?

Phosphorylation. Signup and view all the answers

What is the result of phosphorylation on a serine, threonine, or tyrosine residue?

It creates a phosphate ester. Signup and view all the answers

What is the purpose of a zymogen?

To be stored in an inactive form and later activated. Signup and view all the answers