CONCEPT 8.5: Regulation of enzyme activity helps control metabolism
• Chemical chaos would result if a cell’s metabolic pathways were operating
simultaneously
• Cells can regulate metabolic pathways by switching on or off the genes that encode
specific enzymes, or by regulating the activity of existing enzymes
Allosteric Regulation of Enzymes
• Allosteric regulation occurs when a regulatory molecule binds to a protein at one site
and affects the protein’s function at another site
• This type of regulation may either inhibit or stimulate enzyme activity
Allosteric Activation and Inhibition
• Most allosterically regulated enzymes are made from polypeptide subunits, each with its
own active site
• The complex oscillates between two shapes, one catalytically active and the other
inactive
• An activating or inhibiting molecule may bind to a regulatory site, often located where
the subunits join
• The binding of an activator stabilizes the shape that has functional active sites, whereas
the binding of an inhibitor stabilizes the inactive form of the enzyme
• In cooperativity, substrate binding to one active site triggers a shape change in the
enzyme that stabilizes the active form for all other sites
• This mechanism amplifies the response by priming the enzyme to act on additional
substrate molecules more readily
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anyiamgeorge19. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.89. You're not tied to anything after your purchase.