Question

1. What characteristics of NADH itself and of the NADH dehydrogenase make it necessary to have shuttle systems for transporting cytosolic-reducing equivalents into the matrix?
2. How do all of the changes mediated by HIF-1 work together to reduce the formation of Reactive Oxygen Species?
3. Please explain the physiologic importance of pH in driving IF₁ dimerization. How does dimerization link seemingly distant metabolic pathways?

Answer 1

NADH is impermeable to mitochondrial memebrane. So they use shuttle system to transfer the reducing equivalents for energy production.

In repsonse to low oxygen HIF-1 Alpha act as master regulator. It shifts the aerobic respiration to a anaerobic. It does by activating the glycolyic enzymes and inhibiting the TCA cycle regulators.

IF-1 is more active during Acidic pH but as proton gradient across mitochondrial memebrane leads to increase in pH. At high pH IF1 make tetramer and not able to inhibit the ATP synthase enzyme.

IF-1 dimerization affects the aerobic respiration output, by inhbiting the Oxidative phosphorylation. It happens in most of the cancerous situation which is relied on glycolysis.