What Is a Proton Leak?

A proton leak is a process that occurs in the mitochondria, an organelle within eukaryotic cells

Proton leak is the the movement of protons (H + ions), across the inner membrane of the mitochondria. The mitochondria is a membrane-bound organelle within eukaryotic cells that are the site of oxidative phosphorylation, the end process of sugar breakdown into energy for the cell. Eukaryotic cells are a category of cell that has a membrane-bound nucleus, primarily found in nonbacterial organisms.

Spontaneous Proton Leak

Spontaneous proton leak can occur in a nonspecific manner at the level of protein-lipid interface within the inner mitochondrial membrane.

Protein Mediated Proton Leak

This process is mediated by uncoupling protein (UCP), which can be via indirect or direct transport. UCP1 is also known as thermogenin, which is found primarily in brown adipose tissue.

Physiological Contribution

Proton leak is implicated in the release of energy as protons move back into the mitochondria. This energy is released as heat in brown adipose cells and is an active process during early development and in hibernating animals.

References

• Nature: Definition of Proton Leak
• Medterms: Definition of Mitochonrdia
• CR Society Glossary: Uncoupling Protein (UCP) definition
• MediLexicon,:Thermogenin Definition

Resources

• Mitochondria Research