Thermodynamics And Enzyme Kinetics Flashcards
What does delta G quantify?
How much work is being achieved
Delta G = Free E of Products - Free E of Reactants
What does a decrease in free energy correspond to?
Increase in entropy in the universe
What reactions can happen on their own? Delta G >0 or <0
<0, less than zero
What are reactions with a G < 0 called?
Spontaneous
What are spontaneous reactions ALSO called?
Exergonic, can occur on its own
What are reactions with a delta G greater than 0 called?
Endergonic, cannot occur on their own
What is the delta G of a reaction with reactant and product concentrations reach equilibrium?
0
What usually gives energy to endergonic reactions?
The energy released from ATP hydrolysis
What do catalysts do?
Increase rate of reaction by decreasing the activation free energy and are not consumed in the rxn
Where do substrates bind on an enzyme?
Active site
What is the catalytic cycle reaction?
S + E -> <- ES -> <- P + E
What is v0?
The initial velocity of a reaction
What is Michaelis-Menten Kinetics?
Neglecting the reverse reaction and assuming [S] is constant
What is the Michaelis-Menten Kinetics equation?
V0 = Vmax [S]/ Km + [S]
What are the x and y axis of Michaelis menten kinetics?
X-axis: [S]
Y-axis: Vmax
What does Vmax depend on?
Reaction rate constants and enzyme concentration
What is Km?
The michaelis constant, the value of [S] at which the rate is equal to 1/2 Vmax
What is the Michaelis equation when there is a LOW substrate concentration?
Km + [S] basically equals Km
v0=Vmax[S]/Km
What is the Michaelis equation when there is an INTERMEDIATE [S]?
same as before, v0 = vmax[s]/km+[s]
When [S]=Km, what is v0?
1/2 Vmax
When substrate is HUGE, what is v0?
Vmax
As Enzyme total increases, what happens to Vmax?
It Increases
What is a competitive inhibitor?
An inhibitor that either binds directly to the active site or binds to the enzyme on another part and blocks the active site
Does competitive inhibition affect Vmax?
Yes, it decreases the more inhibitor there is
Will Km be affected competitive inhibition?
Yes, it increases
What is a non competitive inhibitor?
An inhibitor that that doesn’t compete with substrate but also doesn’t allow it to complete the reaction
Does noncompetitive inhibition affect Vmax?
Yes it decreases it
Does noncompetitive inhibition affect Km?
No
What is noncompetitive inhibition the same as?
Removing enzyme
