desmosina

Desmosine, also known as desmosine in English, is a nonstandard cross-linking amino acid that forms part of the elastic fiber protein elastin. It arises during the post-translational cross-linking of four lysine residues within tropoelastin, contributing to the highly elastic properties of elastin-rich tissues.

Desmosine is produced through the action of lysyl oxidase, which oxidatively deaminates lysine residues to form reactive allysine groups. These groups subsequently condense to create a unique tetrafunctional cross-link that links four polypeptide chains. Desmosine exists together with its isomer isodesmosine in mature elastin, and the two are often measured together as desmosine/isodesmosine cross-links due to their structural similarity.

Occurrence and function are closely tied to tissues rich in elastic fibers. Desmosine-containing cross-links stabilize elastin and confer resilience and recoil to tissues such as skin, arteries, lungs, and certain ligaments. The cross-links are largely inert once formed, and elastin’s longevity depends on this network of cross-links.

Detection and clinical relevance: Desmosine and isodesmosine can be measured in urine, plasma, or tissue samples and serve as biomarkers of elastin degradation and turnover. Elevated levels of desmosine-related cross-links are associated with conditions that involve elastolysis, such as tobacco exposure, chronic obstructive pulmonary disease, and certain vascular diseases. Analytical methods include high-performance liquid chromatography and mass spectrometry.

Related compounds: Isodesmosine is a stereoisomeric cross-link that co-occurs with desmosine in elastin. Both are used collectively as indicators of elastin breakdown in biomedical research.