Ball and stick model of the <a href="https://en.wikipedia.org/wiki/Citrulline" class="extiw" title="w:Citrulline">citrulline</a> molecule.
<a href="//commons.wikimedia.org/wiki/User:Benjah-bmm27" title="User:Benjah-bmm27">Ben Mills</a> and <a href="//commons.wikimedia.org/wiki/User:Jynto" title="User:Jynto">Jynto</a>
Derivative of <a href="//commons.wikimedia.org/wiki/File:L-lysine-monocation-from-hydrochloride-dihydrate-xtal-3D-balls.png" title="File:L-lysine-monocation-from-hydrochloride-dihydrate-xtal-3D-balls.png">File:L-lysine-monocation-from-hydrochloride-dihydrate-xtal-3D-balls.png</a> and <a href="//commons.wikimedia.org/wiki/File:Urea-3D-balls.png" title="File:Urea-3D-balls.png">File:Urea-3D-balls.png</a>.