Allosteric Enzymes and Inhibition Vocabulary

Questions and Answers

What is a substrate?

The specific reactant that an enzyme binds to.

What is an enzyme/substrate complex?

A complex that forms when an enzyme binds to its specific substrate.

What is the active site of an enzyme?

A restricted region on the enzyme molecule that binds to the substrate.

What does induced fit refer to?

Chemical groups of the active site are brought into a position that enhances their ability to catalyze the reaction. Signup and view all the answers

How does an enzyme's active site lower activation energy? One way is by _____ substrates correctly.

orienting Signup and view all the answers

Each enzyme has an optimal _____ and pH.

temperature Signup and view all the answers

What are cofactors?

Nonprotein enzyme helpers that can be both organic and inorganic. Signup and view all the answers

What are coenzymes?

Organic cofactors that help enzymes. Signup and view all the answers

What are competitive inhibitors?

Enzyme inhibitors that bind to the active site to compete with the substrate. Signup and view all the answers

What are noncompetitive inhibitors?

Enzyme inhibitors that bind to another part of the enzyme and cause it to change shape, making the active site less effective. Signup and view all the answers

What is an allosteric site?

A site other than the enzyme's active site. Signup and view all the answers

What is allosteric regulation?

The regulation of an enzyme or protein by binding an effector molecule at the protein's allosteric site. Signup and view all the answers

What is an allosteric activator?

A molecule that activates the enzyme. Signup and view all the answers

What is an allosteric inhibitor?

A molecule that binds to the enzyme to make it inactive. Signup and view all the answers

What is allosteric activation?

The increase in an enzyme's activity when an allosteric activator binds to its specific regulatory site. Signup and view all the answers

What is allosteric inhibition?

The active site changes shape when an inhibitor binds to an allosteric site, preventing the substrate from binding. Signup and view all the answers

What is cooperativity?

A form of allosteric regulation that can amplify enzyme activity. Signup and view all the answers

What is enzyme feedback inhibition?

The end product of a metabolic pathway will shut down the pathway to prevent wasting resources. Signup and view all the answers

Study Notes

Enzymatic Concepts

Substrate: The specific reactant that binds to an enzyme for a biochemical reaction.
Enzyme/Substrate Complex: The temporary structure formed when an enzyme and substrate interact.
Active Site: A specialized region on an enzyme where substrate binding occurs, crucial for catalytic activity.
Induced Fit: A model explaining how the active site of an enzyme adapts upon substrate binding to enhance catalysis.

Mechanism of Enzyme Action

Activation Energy Reduction: Enzymes lower activation energy through:
- Correct substrate orientation
- Strain on substrate bonds
- Creating a favorable microenvironment
- Covalent interactions with substrates

Environmental Effects on Enzymes

Temperature and pH Sensitivity: Each enzyme has optimal conditions; for humans, it's approximately 37°C and pH 7.

Enzyme Helpers

Cofactors: Non-protein chemical compounds that assist enzyme function; can be organic (coenzymes) or inorganic; often derived from vitamins.
Coenzymes: Organic cofactors that play a role in enzyme activity, necessary for catalysis.

Inhibition Mechanisms

Competitive Inhibitors: Molecules that compete with substrates by binding to an enzyme's active site.
Noncompetitive Inhibitors: Bind to a different site on the enzyme, altering its shape and function, making the active site less effective.

Regulatory Sites and Mechanisms

Allosteric Site: A distinct site on an enzyme, separate from the active site, where regulatory molecules can bind.
Allosteric Regulation: Modulation of enzyme activity through the binding of effector molecules at allosteric sites.

Types of Allosteric Modulation

Allosteric Activator: A molecule that binds to an allosteric site, enhancing enzyme activity.
Allosteric Inhibitor: Binds to an allosteric site, leading to enzyme inactivity by changing active site shape.

Specialized Allosteric Functions

Allosteric Activation: Increase in enzyme activity upon activator binding to its regulatory site.
Allosteric Inhibition: Conformational changes in the enzyme prevent substrate binding due to inhibitor binding at the allosteric site.
Cooperativity: A phenomenon where substrate binding at one active site increases the likelihood of substrate binding at other active sites, amplifying overall enzyme activity.

Metabolic Control

Enzyme Feedback Inhibition: A regulatory mechanism where the end product of a metabolic pathway inhibits an upstream process, preventing overproduction and conserving resources.

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Description

Test your knowledge on key concepts related to allosteric enzymes and their inhibition. This quiz covers important terms like substrate, enzyme/substrate complex, active site, and induced fit. Expand your understanding of enzymatic functions and mechanisms.