Enzyme Thermodynamics Flashcards
0
Q
What is the change in Gibbs free energy, ΔG?
A
The difference in energy level between the substrates and products.
1
Q
Define the Gibbs free energy of activation.
A
The difference in free energy between the substrate and the transition state
2
Q
What does a negative ΔG mean?
A
This indicates the reaction is thermodynamically favourable.
3
Q
ΔG > 0?
A
The reaction is not thermodynamically favourable
4
Q
Define free energy, G?
A
A measure of energy capable of doing work.
5
Q
In an enzyme catalysed reaction, what is a transition state?
A
An unstable chemical intermediate between the substrates and the products.
6
Q
What effects dos temperature have on enzyme kinetics?
A
- temperature affects the rate of an enzyme catalysed reaction by increasing the thermal energy of the substrate molecules
- this in turn increases the proportion of molecules with sufficient energy to over come the activation energy
7
Q
How does pH affects the kinetics of an enzyme catalysed reaction?
A
- enzymes have an optimum pH at which the rate of the reaction is maximum
- slight deviations in the pH from the optimum lead to a decrease in the reaction rate
- larger deviations result in denaturation due to changes in ionisation of aa residues and disruption of noncovalent interactions.
