Lecture 8 - Enzymes 2

Active Site

The specific region of an enzyme where substrates bind and undergo a chemical reaction.

Enzyme Inhibition

The process in which an inhibitor molecule binds to an enzyme and decreases its activity.

Allosteric Effectors

Molecules that bind to an enzyme at a site other than the active site and induce a conformational change, affecting enzyme activity.

Competitive Inhibition

A type of enzyme inhibition where the inhibitor competes with the substrate for binding to the active site.

Noncompetitive Inhibition

A type of inhibition where the inhibitor binds to an enzyme at a site other than the active site, reducing enzyme activity regardless of substrate concentration.

Reversible Inhibition

A type of inhibition where the inhibitor can bind and unbind from the enzyme, allowing the enzyme to regain activity.

Irreversible Inhibition

A type of inhibition where the inhibitor forms a permanent bond with the enzyme, leading to a lasting decrease in enzyme activity.

Induced Fit Model

A model of enzyme activity where the binding of the substrate induces a change in the shape of the enzyme, enhancing the fit and facilitating the reaction.

Isoenzymes

Enzymes that differ in amino acid sequence but catalyze the same reaction, often with different regulatory properties.

Feedback Inhibition

A regulatory mechanism in metabolism where the end product of a pathway inhibits an upstream process.

The ________ is the specific region of an enzyme where substrates bind and undergo a chemical reaction.

Active Site

________ inhibition occurs when the inhibitor competes with the substrate for binding to the active site.

Competitive

The process in which an inhibitor molecule binds to an enzyme and decreases its activity is called ________ inhibition.

Enzyme Inhibition

In ________ inhibition, the inhibitor binds to an enzyme at a site other than the active site, reducing enzyme activity regardless of substrate concentration.

Noncompetitive

The ________ model describes how the binding of the substrate induces a change in the shape of the enzyme, enhancing the fit and facilitating the reaction.

Induced Fit

________ inhibitors can bind and unbind from the enzyme, allowing the enzyme to regain activity.

Reversible

In ________ inhibition, the inhibitor forms a permanent bond with the enzyme, leading to a lasting decrease in enzyme activity.

Irreversible

________ effectors are molecules that bind to an enzyme at a site other than the active site and induce a conformational change.

Allosteric

Feedback inhibition is a regulatory mechanism in metabolism where the end product of a pathway ________ an upstream process.

inhibits

________ are enzymes that differ in amino acid sequence but catalyze the same reaction, often with different regulatory properties.

Isoenzymes

What is the primary function of enzymes in biological systems?

Enzymes act as catalysts that accelerate chemical reactions in biological systems.

What factors can affect enzyme activity?

Enzyme activity can be affected by temperature, pH, substrate concentration, and the presence of inhibitors or activators.

What is the role of a substrate in enzyme reactions?

A substrate is a specific molecule upon which an enzyme acts, undergoing a chemical reaction.

What is the difference between competitive and noncompetitive inhibitors?

Competitive inhibitors compete with substrates for the active site, while noncompetitive inhibitors bind to a different site, affecting enzyme activity regardless of substrate presence.

What is an enzyme's active site comprised of?

The active site is typically formed by the folding of the enzyme, containing specific amino acids that interact with the substrate.

How do allosteric effectors influence enzymes?

Allosteric effectors bind to an enzyme at a site other than the active site, causing conformational changes that can increase or decrease enzyme activity.

What is the significance of reversible inhibition?

Reversible inhibition allows enzymes to regain activity when the inhibitor is removed, providing control over enzyme function.

What occurs during feedback inhibition in metabolic pathways?

In feedback inhibition, the end product of a metabolic pathway inhibits an earlier step in the pathway to regulate production.

Why are isoenzymes important?

Isoenzymes allow for regulation of metabolic pathways and can have different properties or regulatory actions in different tissues.

What does the term 'induced fit' refer to in enzyme activity?

Induced fit refers to the change in shape of an enzyme upon substrate binding, enhancing the fit and facilitating the catalysis of the reaction.