Proteins (c) (ii) Ligand Binding Changes the Conformation of a Protein Flashcards
A ligand is…
A substance that can bind to a protein
R groups not involved in protein folding can allow…
Binding to Ligands
Binding sites will have…
Complimentary shape and chemistry to the ligand.
As a ligand binds to a protein-binding site…
The conformation of the protein will change. The change in conformation causes a functional change in the protein.
Allosteric sites occur between…
Spatially distinct sites
Many allosteric proteins consist of…
Multiple subunits (have quaternary structure)
Allosteric proteins with multiple subunits show…
Cooperativity in binding, in which changes in binding at one subunit alter the affinity of the remaining subunits.
Allosteric enzymes contain a second type of site, called an…
Allosteric site.
What does a modulator do?
Regulates the activity of the enzyme when they bind to the allosteric site. Following the binding of a modulator, the conformation of the enzyme changes and this alters the affinity of the active site for the substrate.
The binding and release of oxygen in haemoglobin shows…
Co-operativity
The binding of a substrate molecule to one active site of an allosteric enzyme increases…
The affinity of the other active sites for binding of subsequent substrate molecules.
This is of biological importance because…
The activity of allosteric enzymes can vary greatly with small changes in substrate concentration.
Positive modulators increase the…
Enzymes affinity for the substrate
Negative modulators reduce the…
Enzymes affinity for the substrate
Changes in binding of oxygen at one subunit…
Alter the affinity of the remaining subunits for oxygen.
