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.

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).

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).

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.

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.

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

Sources: ELN: Elastin (human) (UniProt, 2026); ELN gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Elastic fibre formation (Reactome, 2026); Supravalvular aortic stenosis: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Cutis laxa: MedlinePlus Genetics (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.