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[Biochemistry](https://durgical.com/en/biochemistry/) · Protein

# Elastin

Elastin lets arteries, lungs and skin stretch and spring back; it is built on a scaffold of fibrillin.

Updated 2026-11-01

## Key facts

- Secreted as tropoelastin (ELN gene, chromosome 7) and laid down on fibrillin microfibrils.
- Rich in glycine, alanine, valine and proline; little hydroxyproline, no hydroxylysine and no triple helix.
- Lysyl oxidase (copper-dependent) joins four lysines from neighbouring chains into desmosine and isodesmosine, cross-links unique to elastin.
- Neutrophil elastase degrades it; α1-antitrypsin restrains that elastase and protects the lung.

**Also called**
Tropoelastin, Elastic fibres

**Genes**
ELN

## Structure

- There is no crystal structure of whole elastin: it is deliberately disordered, with flexible hydrophobic domains alternating with lysine-rich cross-linking domains.
- When stretched, its hydrophobic segments are exposed to water; when released, they collapse back on their own (elastic recoil).

## Regulation

- It is made mainly in fetal life and childhood; in adults it barely turns over and lasts for decades.
- It is degraded by neutrophil elastase and metalloproteinases (macrophage MMP-12).

## Inhibitors and toxins

- Neutrophil elastase (degradation, restrained by α1-antitrypsin)
- Copper deficiency (inactive lysyl oxidase)

## Clinical notes

- Emphysema: cigarette smoke draws in neutrophils and oxidises α1-antitrypsin; elastase is left free and destroys alveolar walls.
- Williams syndrome (7q11.23 deletion including ELN) and isolated supravalvular aortic stenosis (ELN variants): narrow, stiff arteries.
- Cutis laxa: loose, inelastic skin from variants in ELN or other elastic-fibre genes.
- With age and sun, skin elastin fragments (solar elastosis): wrinkles.

## Related conditions

- [α1-antitrypsin deficiency](https://durgical.com/en/conditions/1-antitrypsin-deficiency/)
- [Chronic obstructive pulmonary disease (COPD)](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/)
- [Menkes disease](https://durgical.com/en/conditions/menkes-disease/)
- [Abdominal aortic aneurysm](https://durgical.com/en/conditions/abdominal-aortic-aneurysm/)

## Related

- [Fibrillin-1](https://durgical.com/en/biochemistry/enzymes/fibrillin-1/)
- [Collagen](https://durgical.com/en/biochemistry/enzymes/collagen/)
- [Collagen synthesis](https://durgical.com/en/biochemistry/topics/collagen-synthesis/)
- [Copper](https://durgical.com/en/biochemistry/topics/copper/)
- [α1-antitrypsin](https://durgical.com/en/biochemistry/enzymes/1-antitrypsin/)

## Test yourself

Think of the answer, then tap the question to see it.

## Which cross-links are unique to elastin?

Desmosine and isodesmosine, formed by lysyl oxidase from four lysines.

## Which protein protects lung elastin from neutrophil elastase?

α1-antitrypsin; when it is lacking, early emphysema develops.

## How does elastin differ from collagen?

It forms no triple helix, has almost no hydroxyproline or hydroxylysine and is cross-linked by desmosine; it stretches and recoils.

## Which cardiovascular lesion is linked to ELN variants?

Supravalvular aortic stenosis, alone or as part of Williams syndrome.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: [ELN: Elastin (human)](https://www.uniprot.org/uniprotkb/P15502/entry) (UniProt, 2026); [ELN gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/eln/) (MedlinePlus, US National Library of Medicine, 2026); [Elastic fibre formation](https://reactome.org/PathwayBrowser/#/R-HSA-1566948) (Reactome, 2026); [Supravalvular aortic stenosis: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/supravalvular-aortic-stenosis/) (MedlinePlus, US National Library of Medicine, 2026); [Cutis laxa: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/cutis-laxa/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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Representative model, for educational purposes only.

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