Lecture 12 - control of enzyme activity Flashcards
1
Q
what is an inhibitor
A
a compound that binds to an enzyme and reduces its activity
2
Q
what is irreversible inhibition
A
- binds covalently
- permanently inactivates that enzyme
3
Q
what is reversible inhibition
A
- not covalently bound
- binds to the enzyme but then can subsequently be released
4
Q
what is competitive inhibition
A
- inhibitor competes directly with the substrate for the active site
- either inhibitor or substrate will bind to the enzyme
5
Q
what happens to Vmax and Km in competitive inhibition
A
- Vmax stays the same
- Km increases
6
Q
what is pure non competitive inhibition
A
- inhibitor binds at a different site than the substrate
- enzyme can bind to substrate or inhibitor or both at the same time
7
Q
what happens to Vmax and Km in pure inhibition
A
- Vmax decreases
- Km stays the same
8
Q
what happens in mixed inhibition
A
changes in both Vmax and Km
9
Q
what are the methods of enzyme regulation (5)
A
- covalent modification (e.g phosphorylation)
- allosteric effects = binding at points not active site
- proteolytic cleavage (e.g gut proteases, made in inactive form and then activated
- turn gene expression on or off
- degrade the enzyme
