February 27, 2023
I’m like a rubber band in your body.
What molecule am I?
Image of Elastin 3D Image of Elastin

Writing in the Encyclopedia of Biological Chemistry II, biochemist Judith Ann Foster of Boston University describes elastin as

a protein that exists as fibers in the extracellular spaces of many connective tissues. Elastin derives its name from its ability to act as an elastic band, that is, to stretch and recoil with transient force. It is located throughout many tissues and organs of higher vertebrates and plays an important functional role in maintaining pressures associated with liquid and air flow in the cardiovascular and pulmonary systems.

Elastin takes many forms and compositions depending on its location in the organism. In a 1938 report on the composition of elastin, William A. Stein and Edgar G. Miller, Jr., at Columbia University (New York City) identified and quantified 10 amino acids, the most abundant of which were glycine and leucine.

The images show one of the common structures within elastin: the peptide chain N-acetyl-L-leucyl-L-isoleucyl-glycyl-L-valyl-L-proline methylamide. Although components of elastin, called tropoelastins, are water-soluble, the large elastin protein is not.

In some respects, elastin is similar to titin, the Molecule of the Week for November 7, 2022. In humans, titin is encoded by the TTN gene in chromosome 2; elastin is coded by ELN in chromosome 7.

For additional information on elastin, see ScienceDirect’s abstract page.

Elastin hazard information

Hazard class*GHS code and hazard statement
Not a hazardous substance or mixture 

*Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. 

MOTW updates

Hydrogen peroxide (H2O2) was the Molecule of the Week for January 26, 2007. It was updated in August 2022 with two articles describing the use of the oxygen reduction reaction to prepare H2O2. This past week, another H2O2 synthesis appeared: Siji Ogo and co-workers at Kyushu University (Fukuoka, Japan) described a one-pot, homogeneously catalyzed reaction between oxygen and hydrogen in aqueous solvent to make H2O2 under ambient conditions. The process uses a rhodium-based catalyst system and avoids explosive H2–O2 mixtures.

Carbon nitride (C3N4) was the Molecule of the Week for January 16, 2023. Among its several allotropes, β-C3N4 has properties similar to those of diamond, whereas the properties of g-C3N4 are more like graphite. g-C3N4 has valuable semiconductor and photocatalytic properties; but earlier this month, Hanning Chen, Danmeng Shuai, and colleagues at the University of Texas at Austin, the George Washington University (Washington, DC), and four other institutions reported that g-C3N4 nanosheets are readily oxidized by reactive chlorine species (RCS). The authors found that the free radicals ClO and Cl2 decompose the sheets more rapidly than other RCS.

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Elastin fast facts

CAS Reg. No.9007-58-3
SciFinder nomenclatureElastins
Empirical formulaC27H48N6O6 (component)
Molar mass552.71 g/mol (component)
AppearancePale yellow fibers
Melting pointN/A
Water solubilityInsoluble
Chemical Abstract Service - a division of ACS

Learn more about this molecule from CAS, the most authoritative and comprehensive source for chemical information.

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