Elastin: structure, properties and metabolism

Soluble tropoelastin is a precursor of elastin. It is transported by elastin binding protein (EBP) into intercellular space. The EBP-tropoelastin complex undergoes disintegration in the intercellular space. EBP returns to the cell and tropoelastin joins with microfibril proteins. Lysine residues of tropoelastin undergo oxidative deamination. Desmosine, isodesmosine and cross bonds arise. Thus tropoelastin loses solubility and transforms to elastin. The elastic fiber created consists of microfibrils on the periphery and an elastin core inside. Elastin provides blood vessels, lungs, cartilage and skin with the ability to reverse deformations. A decrease of elastin content or changes in this protein structure results in pathological conditions such as aneurysms and pulmonary emphysema.