Enzyme Kinetics Flashcards
What does it mean for a reaction to reach its “steady state”?
Formation of the enzyme substrate equals the loss of enzyme substrate
How does positive co-op binding affect substrate affinity? Give an example
It increases affinity for subsequent substrate; hemoglobin exhibits positive co-op binding b/c it binds 4 O2 molecules
How does negative co-op binding affect substrate affinity?
It decreases affinity for subsequent substrate
How does non co-op binding affect substrate affinity? Give an example
Does not affect affinity for subsequent substrate; myoglobin exhibits non co-op binding because it only binds 1 O2 molecule
Give an example of a receptor binding a signaling molecule in response to a stimuli.
E.g. insulin binding to a ligand in response to increases in blood-glucose
When discussing non-enzymatic transport proteins, what does concentration mean for the ligand affinity?
Hi concentration = hi affinity
Lo conentration = lo affinity
Given that ∆G’° for the reaction S⇋P is negative in the direction of S→P, reaction equilibrium favors the formation of which substance?
P; a negative ∆G means the rxn is thermodynamically favorable
How would the addition of a catalyst to the reaction S⇋P affect the difference between the free energies of S and P in their ground states (∆G’°)?
∆G’° would not change; enzymes DO NOT change free energy
If the enzyme-catalyzed reaction E + S ⇋ ES ⇋ E + P is proceeding at the V_{max}what can be deduced about the concentrations of S and ES?
S has saturated the solution, [ES] is at its highest point
What relative values of Km and k_{cat} would describe an enzyme with a high catalytic efficiency?
Low Km: concentration of substrate when rxn velocity is at 50%
Hi K cat: speed at which {ES complex} becomes E+P
With respect to the binding of regulatory compounds, what properties define an enzyme as being allosteric?
Reversible, non covalent, binds regulatory compounds
Assuming all other reaction conditions remain constant and that the reaction is allowed to proceed to equilibrium, how would the reaction S⇋P be affected by the addition of an enzyme catalyst?
Increased rxn rate
