# 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.

## Sources

- Stadtman ER. (1992). Protein oxidation and aging. Science. https://doi.org/10.1126/science.1355616
- Nystrom T. (2005). Role of oxidative carbonylation in protein quality control and senescence. EMBO Journal. https://doi.org/10.1038/sj.emboj.7600599

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