Bio Chemistry

BIOCHEMISTRY 3(2+1)

Lesson 31 : Biochemical energetics and biological oxidation

Regulation of oxidative phosphorylation

1. Depends upon substrate availability and energy demands in the cell.
2. Important substrates are NADH, O2, and ADP.
3. As ATP is used, more ADP is available, translocated through adenine nucleotide translocase --> electron transport increases.
4. Known as respiratory control.
5. Helps to replenish ATP pool in the cell, which is kept nearly constant.
6. Rates of glycolysis, citric acid cycle, and electron transport system are matched to a cell’s ATP requirements.
7. Proton gradient can be short-circuited to generate heat
8. Found in brown adipose tissue in newborn mammals and animals that hibernate, and animals adapted to cold conditions
9. A protein called thermogenin forms a proton channel in inner mitochondrial membrane --> dissipates proton gradient, but electrons still flow --> heat production
10. Pathway is activated by fatty acids from triacylglycerol catabolism from epinephrine stimulation