IB Biology Topic C1.1.14 Allosteric Sites and Non-competitive Inhibition Revision Notes (HL)

IB Biology Topic C1.1.14 Allosteric Sites and Non-competitive Inhibition Revision Notes (HL) | RevisionDojo

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An Allosteric Site Is a Second Binding Site Away From the Active Site

An enzyme's active site is where the substrate binds and the reaction is catalysed.
Many enzymes also have an allosteric site, a separate binding site located elsewhere on the enzyme.
Only specific molecules, called allosteric regulators, bind there, and they are often products or intermediates of a metabolic pathway.
Binding at the allosteric site is reversible, so the enzyme returns to its original state once the regulator leaves.

Definition

Allosteric site

A site on an enzyme other than the active site, where specific molecules can bind to regulate enzyme activity.

Analogy

Think of the enzyme as a flexible tool.
Binding at the allosteric site is like turning a screw on the tool, changing its shape and how well it works.

Binding at the Allosteric Site Changes the Enzyme's Shape

When a regulator binds to the allosteric site, it triggers a conformational change in the enzyme.
This reshapes the active site, either boosting or blocking its ability to catalyse the reaction.
Allosteric activation
1. An activator reshapes the active site so it binds substrate more readily, raising enzyme activity.
Allosteric inhibition

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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An Allosteric Site Is a Second Binding Site Away From the Active Site

An enzyme's active site is where the substrate binds and the reaction is catalysed.
Many enzymes also have an allosteric site, a separate binding site located elsewhere on the enzyme.
Only specific molecules, called allosteric regulators, bind there, and they are often products or intermediates of a metabolic pathway.
Binding at the allosteric site is reversible, so the enzyme returns to its original state once the regulator leaves.

Definition

Allosteric site

A site on an enzyme other than the active site, where specific molecules can bind to regulate enzyme activity.

Analogy

Think of the enzyme as a flexible tool.
Binding at the allosteric site is like turning a screw on the tool, changing its shape and how well it works.

Binding at the Allosteric Site Changes the Enzyme's Shape

When a regulator binds to the allosteric site, it triggers a conformational change in the enzyme.
This reshapes the active site, either boosting or blocking its ability to catalyse the reaction.
Allosteric activation
1. An activator reshapes the active site so it binds substrate more readily, raising enzyme activity.
Allosteric inhibition

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C1.1.14: Allosteric Sites and Non-competitive Inhibition Notes

An Allosteric Site Is a Second Binding Site Away From the Active Site

Binding at the Allosteric Site Changes the Enzyme's Shape

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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An Allosteric Site Is a Second Binding Site Away From the Active Site

Binding at the Allosteric Site Changes the Enzyme's Shape

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics