Difference Wiki

Allosteric Site vs. Active Site: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on January 6, 2024
An allosteric site is a separate site where regulators bind to alter enzyme activity, while The active site of an enzyme is where substrate molecules bind and react.

Key Differences

The active site of an enzyme is a specific region where substrate molecules bind and undergo a chemical reaction. In contrast, the allosteric site is a distinct site on the enzyme, separate from the active site, where allosteric regulators (activators or inhibitors) bind.
Allosteric sites allow for the regulation of enzyme activity; binding of molecules to these sites can either increase or decrease the enzyme's activity. The active site, however, is directly involved in the catalytic process, where the conversion of substrate to product occurs.
The presence of allosteric sites enables enzymes to be more precisely controlled within the cell, responding to the needs of the cell. Active sites are critical for the enzyme's primary function, which is to lower the activation energy of specific biochemical reactions.
Allosteric regulation, occurring at the allosteric site, can change the shape of the enzyme and consequently affect the activity of the active site. The active site, by its nature, remains relatively unchanged except for the transient binding of substrates and release of products.
In terms of structure, allosteric sites are often located at a considerable distance from the active site, affecting the enzyme's function through conformational changes. The active site, in contrast, is typically a pocket or groove on the enzyme's surface, specifically shaped to fit the substrate molecules.

Comparison Chart


Regulates enzyme activity
Catalyzes the reaction of substrates


Separate and often distant from the active site
Specific region where substrates bind

Binding Molecules

Allosteric regulators (activators or inhibitors)
Substrate molecules

Effect on Enzyme

Can alter the shape and activity of the enzyme
Direct involvement in the catalytic process

Role in Cellular Processes

Controls and modulates enzyme activity
Fundamental for enzyme's catalytic function

Allosteric Site and Active Site Definitions

Allosteric Site

Alters the shape of the enzyme, affecting the active site.
The allosteric site's occupation triggered a conformational change in the enzyme.

Active Site

Key to enzyme specificity and function.
The unique structure of the active site dictates the enzyme's specificity for its substrate.

Allosteric Site

Essential for the fine-tuning of metabolic pathways.
Allosteric site interactions are crucial for controlling metabolic fluxes in cells.

Active Site

Specifically shaped to accommodate the substrate.
Due to the complementary shape, the substrate was effectively bound at the active site.

Allosteric Site

Can either activate or inhibit the enzyme's function.
An inhibitor bound to the allosteric site, reducing the enzyme's efficiency.

Active Site

Responsible for converting substrate to product.
The active site facilitated the transformation of the substrate into its product.

Allosteric Site

A regulatory site on an enzyme separate from the active site.
The enzyme's activity was increased due to a molecule binding to its allosteric site.

Active Site

The region on an enzyme where substrates bind and react.
The substrate fits precisely into the enzyme's active site, initiating the reaction.

Allosteric Site

Influences enzyme activity without directly participating in catalysis.
Binding at the allosteric site caused a decrease in the enzyme's reaction rate.

Active Site

Directly involved in the enzyme's catalytic process.
The chemical reaction occurred rapidly at the enzyme's active site.


What is an allosteric site?

A site on an enzyme separate from the active site, regulating its activity.

What is an active site?

The part of an enzyme where substrates bind and undergo a reaction.

Can allosteric sites activate enzymes?

Yes, some allosteric regulators are activators.

What happens at an enzyme's active site?

Substrate molecules bind and are converted into products.

How does the allosteric site influence enzyme activity?

By binding regulators that change the enzyme's shape and activity.

Do all enzymes have allosteric sites?

Not all, but many enzymes have allosteric sites for regulation.

How does allosteric regulation affect metabolic pathways?

It modulates enzyme activities, influencing the flow of metabolic pathways.

What determines an enzyme's specificity?

The shape and characteristics of its active site.

Are allosteric sites common in enzymes?

Many enzymes have allosteric sites for regulation.

What's the difference between allosteric and competitive inhibition?

Allosteric inhibition occurs at a separate site, while competitive inhibition occurs at the active site.

Is the active site involved in enzyme regulation?

No, it's primarily for substrate binding and reaction.

How does an inhibitor at an allosteric site work?

It binds to the allosteric site and decreases enzyme activity.

What are allosteric activators?

Molecules that bind to the allosteric site and increase enzyme activity.

How do allosteric sites contribute to enzyme efficiency?

They allow fine-tuning of enzyme activity, enhancing overall metabolic efficiency.

Can multiple substrates bind to an active site?

Typically, only specific substrates bind to a given active site.

Can the active site change its shape?

It may change slightly upon substrate binding.

How is enzyme activity measured?

By the rate of substrate conversion at the active site.

Is the active site always open for substrate binding?

It's available for binding when the enzyme is in the right conformation.

What's the role of the active site in catalysis?

It lowers the activation energy for the reaction.

Can an enzyme have multiple allosteric sites?

Yes, some enzymes have multiple allosteric sites for different regulators.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

Trending Comparisons

Popular Comparisons

New Comparisons