Regulation Of OxPhos Flashcards
Does the F1 subunit bind to both ATP and ADP
Yes
What controls the rate of the TCA Cycle?
The availability of NAD+ and FAD
Relationship b/w Delta E0 and Delta G0
They are INVERSELY proportional
What is E0?
The standard Redox Potential
Role of Inhibitory factor 1 (IF1)
- Inhibits the hydrolytic activity of ATP Synthase
- Prevents the Reverse Rxn (ATP Breakdown)
What Inhibits ATP synthesis?
Oligomycin
- by disrupting the proton transport through the channel
Characteristics of the subunits of the F1 subunit
- 3 alpha, 3 beta, a gamma, delta and epsilon
(9 in total) - alpha and beta are arranged in a HEXAMERIC ring
- epsilon and gamma make the STALK above the a/b hexa-ring
- gamma subunit had a long coil that extends to the center of the hexamer
Structure of ATP synthase.
AKA?
- Ball and stick structure
- Has 2 subunits
1. F0
2. F1
AKA Complex V
Purpose of the Cristae in the Mitochondria?
To allow the proton gradient to be in close PROXIMITY to the ATP Synthase.
What inhibits the ATP-ADP Translocase?
- Atractyloside
2. Bongkrekic acid
Glycerophosphate Shuttle
- Where it operates?
- What it generates and where?
- Where it enters the ETC?
- It operates in the Muscle and the Brain
- It generates FADH2
- It enters at Complex II
— But it joins the ETC at CoQ (Ubiquinone)
What happens when a transfer of e- are inhibited?
- A decrease in the pumping protons
- A decrease in the protein gradient
- Inhibition of ATP synthesis
How can NADH and FADH2 cross the mitochondrial membrane
Via the 2 shuttle systems
- Malate-Aspartate Shuttle (NADH)
- Glycerophosphate shuttle (FADH2)
Characteristics of the F1 subunit?
- Bass that protrudes into the MATRIX
- Contains catalytic domains
Where is the Oligomycin inhibiting region?
On the F0 subunit of ATP Synthase
What in the cell regulates cell respiration?
Levels of ATP
Can ATP/ADP move across the mitochondrial membrane?
No
It needs a carrier
-Translocase
Flow of E- in the ETC
E- flow from the molecules with LOWER E0 to those with HIGHEST E0
Chemiosmotic Theory’s Postulates?
- The ETC moves Protons across the inner membrane as e- flow from one complex to the next
- ATP sythase uses pmf to Phosphate ADP
- Inner membrane is IMPERMEABLE to H+ and OH-. If membrane is disrupted, the pmf cannot be est.
- ATP synthesis is lost
How does Thermogenin (aka UCP 1) generate heat?
- Pumps protons form the CYTOPLASM to the MATRIX
- Energy is converted to Heat instead of ATP
What two systems are linked by delta pmf?
- Respiratory chain
And
- ATP synthase
Which subunit of the F1 subunit binds to nucleotides?
BOTH A and B
BUT Beta is the Catalytically ACTIVE site
Malate-Aspartate Shuttle
- Where it operates
- What it generates and where?
- Where does it enter the ETC
- Operates in the Heart, Liver, and Kidneys
- Generated NADH in the Mitochondria Matrix
- NADH enters to ETC at Complex 1
Characteristics of F0 subunit?
- Stick embedded in the membrane
- Has proton CHANNEL
What factors constitute the pmf to drive ATP synthesis?
- pH gradient
2. Membrane potential
Characteristics of Translocase?
- Reside in the Outer and Inner membranes of the Mitochondria
- Flow of ATP/ADP is COUPLED
ADP ENTERS the Matrix ONLY if ATP LEAVES
What happens when you uncouple OxPhos from ATP synthesis
Heat generation
