Lysyl oxidase

Lysyl oxidase is an enzyme which speeds up coacervation, a reaction which attaches protoelastin molecules to each other, creating the protein elastin. Elastin is a component of the human skin which lets it stretch without being deformed permanently.
Lysyl oxidase is made up of various amino acids (the building blocks of proteins) which make up the final protein: elastin. Elastin is made of valine, alanine, glycine, and proline.