Cytochrome c oxidase (also called Complex IV) is an enzyme complex found in the inner mitochondrial membrane.
- It is the last enzyme in the electron transport chain (ETC) — the process cells use to generate energy.
- Its main job: transfer electrons from cytochrome c to oxygen (O₂), forming water.
🔬 Explanation (What It Does & Why It Matters)
1. Role in Energy Production
- Cytochrome c oxidase accepts electrons carried by cytochrome c.
- It passes these electrons to oxygen (the final electron acceptor).
- At the same time, it pumps protons (H⁺) across the mitochondrial membrane.
- This creates the proton gradient used by ATP synthase to generate ATP (adenosine triphosphate) — the cell’s main energy currency.
👉 Without cytochrome c oxidase, aerobic organisms could not efficiently make energy.
2. Structure
- A large multi-subunit protein complex embedded in the inner mitochondrial membrane.
- Contains metal cofactors: heme groups and copper centers, crucial for transferring electrons.
3. Medical & Biological Relevance
- Deficiency (rare genetic disorders) → causes muscle weakness, neurological problems, and sometimes fatal metabolic conditions.
- Toxic inhibition: Poisons like cyanide and carbon monoxide block cytochrome c oxidase, preventing oxygen use → leads to cellular suffocation.
- Red light therapy: Cytochrome c oxidase is thought to absorb red/near-infrared light, which boosts its activity, enhances electron flow, and increases ATP production. This is one reason why red light is studied for healing and regeneration.
⚡ Summary
Cytochrome c oxidase = Complex IV of the mitochondrial electron transport chain.
It’s the key enzyme that transfers electrons to oxygen, drives ATP production, and is even responsive to red/infrared light stimulation.