desmosin

Desmosin is a term sometimes used to refer to desmosine, a unique cross-linking amino acid found in elastin, the protein that gives connective tissue its elasticity. Desmosine is formed by the oxidative coupling of four lysine-derived residues during elastin maturation, producing a tetrafunctional cross-link that ties elastin strands together and contributes to the resilience of tissues such as skin, lungs, and blood vessels.

Biosynthesis occurs in elastic fibers through the action of lysyl oxidase, which oxidizes lysine residues to form reactive allysine groups. These groups condense to generate the desmosine cross-link, often alongside its structural isomer isodesmosine. Desmosine is enriched in mature elastin and is not commonly incorporated into other proteins.

Analytical use of desmosine and isodesmosine centers on measuring elastin turnover and degradation. Elevated levels can indicate increased elastin breakdown, which is observed in conditions such as emphysema, chronic obstructive pulmonary disease, aging, and exposure to tobacco smoke. Conversely, lower or stable levels may reflect reduced elastin degradation or altered tissue remodeling.

In research and clinical contexts, desmosine serves as a biomarker for elastin remodeling in cardiovascular and pulmonary diseases, as well as for assessing aging processes. See also elastin; desmosine; isodesmosine.