Enzyme Inhibition Flashcards
List the 3 types of enzyme inhibition.
- Competitive
- Uncompetitive
- Mixed
How does a competitive inhibitor react to an enzyme?
It binds to the active site and competes with the substrate
How does a non-competitive inhibitor react with an enzyme?
It binds to the allosteric site and changes the shape of the active site of the enzyme
What is mixed inhibition?
Inhibition where both competitve and uncompetitive inhibition occurs
What are cofactors?
Non-protein enzyme helpers
What cofactor complexes with methemoglobin?
Fe³⁺
What cofactor complexes with hemoglobin?
Fe²⁺
Give 3 examples of cofactors.
Zinc, iron, and copper
Cofactors can bind …. to the enzyme.
Permanently or reversibly
What are coenzymes?
Inorganic cofactors
Give some examples of coenzymes.
B Vitamins
What cofactor complexes with methemoglobin?
Fe³⁺
What is Feedback Inhibition?
It is a process whereby an early step in a metabolic pathway is switched off by the pathway’s final product.
Give an example of Feedback Inhibition.
Isoleucine Production
What is the substrate used for Isoleucine Production?
Threonine
Why is Feedback Inhibition useful for a cell?
It prevents the cell from wasting chemical resources by preventing synthesising more product than is needed.
What is Allosteric Regulation?
This is when a protein’s function at one site is affected by the binding of a regulatory molecule at another site.
Most allosterically-regulated enzymes consist of how many polypeptides?
2 or more
How does an activator affect an enzyme?
It stabilises the active form of the enzyme by binding to the allosteric/ regulatory site.
How does an inhibitor affect an enzyme?
It stabilises the inactive form of the enzyme by binding to its allosteric/ regulatory site.
What is co-operativity?
A form of allosteric regulation that can increase enzyme activity.
How does co-operativity work?
A substrate binds to an active site on one of the subunits of the active form of enzyme, which locks all the subunits into the active conformation.
