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Cytochrome c as an electron shuttle between the outer and inner mitochondrial membranes
The Journal of Biological Chemistry
|July 25, 1981
Summary
Exogenous NADH oxidation in mitochondria involves a pathway from NADH-cytochrome b5 reductase to cytochrome b5, then to intermembrane cytochrome c, and finally to cytochrome oxidase. This process is influenced by ionic strength and cytochrome c
Area of Science:
- Biochemistry
- Mitochondrial Function
- Electron Transport Chain
Background:
- Mitochondria utilize electron transport chains for ATP production.
- The roles of specific cytochromes in electron transfer are crucial for cellular respiration.
Purpose of the Study:
- To elucidate the pathway of exogenous NADH oxidation in mitochondria.
- To investigate the role of cytochrome c in intermembrane electron transfer.
Main Methods:
- Mitochondrial oxygen uptake measurements.
- Spectrophotometric analysis of cytochrome reduction and reoxidation.
- Inhibition studies using mersalyl.
Main Results:
- Exogenous NADH oxidation involves cytochrome b5 and cytochrome c.
- NADH oxidation rate and cytochrome c reduction are dependent on ionic strength.
- Succinate oxidation rate decreases with increasing ionic strength.
Conclusions:
- Aerobic oxidation of exogenous NADH follows the pathway: NADH → NADH-cytochrome b5 reductase → cytochrome b5 → intermembrane cytochrome c → cytochrome oxidase → oxygen.
- Cytochrome c's function as an inner membrane carrier and intermembrane shuttle are alternative.
- Mitochondrial intermembrane communication via cytochrome c may regulate cytosolic redox reactions.