Protein carbonylation

Protein carbonylation is a permanent kind of oxidative damage to your proteins. It happens when carbonyl groups (aldehydes or ketones) get stuck onto a protein's side chains, usually at proline, arginine, lysine, or threonine. Two routes cause it: direct metal-catalyzed oxidation, or attack by reactive fat fragments like 4-HNE. Once carbonylated, a protein is bent out of shape. It tends to clump, and the cell's proteasome cannot break it down well, so it piles up as a sign of protein-quality stress. Carbonyl levels rise steadily with biological age across species. They are also high in tissues hit by Alzheimer's, Parkinson's, and COPD. That makes carbonylation a widely used marker of cumulative oxidative damage.

Last reviewed: June 22, 2026

This definition is educational and is not medical advice, a diagnosis, or treatment. Talk to a doctor about any health decisions. Read our full medical disclaimer