Isodesmosine

**Definition:** 2-(4-Amino-4-carboxybutyl)-1-(5-amino-5-carboxypentyl)-3,5-bis(3-amino-3-carboxypropyl)pyridinium. A rare amino acid found in elastin, formed by condensation of four molecules of lysine into a pyridinium ring.

**Tree numbers:** - D03.383.725.762.500 - D12.125.072.415