Elastin

elastin [i′las·tən]

(biochemistry)

An elastic protein composing the principal component of elastic fibers.

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Elastin 

the scleroprotein that is the chief constituent of elastic fibers of connective tissue. Elastin is especially abundant in the cervical ligaments and the aortic walls (about 40 percent of the dry mass). The amount of elastin in lung tissue increases with age from 0.05 to 15 percent of the dry mass. Elastin is insoluble (even when heated) in water, dilute saline solutions, acids, and alkalies. It contain a large number of amino acid radicals with nonpolar side chains, which appear to be responsible for the high elasticity of its fibers. Like collagen, elastin is rich in glycine and proline.

Elastin can be broken down only with difficulty by proteolytic enzymes. It is digested in the digestive tract mainly as a result of the action of the enzyme elastase. Elastin is found in all vertebrates except cyclostomes; it is absent in invertebrates.

REFERENCES

Haurowitz, F. Khimiia i funktsii belkov, 2nd ed. Moscow, 1965. (Translated from English.)
Elastin and Elastic Tissue. New York–London, 1977.