Hypusine is an uncommon amino acid found in all eukaryotes and in some archaea, but not in bacteria.

The region surrounding the hypusine residue is highly conserved and is essential to the function of eIF5A.

[2] Thus, hypusine and eIF-5A appear to be vital for the viability and proliferation of eukaryotic cells.

Two reactions and two enzymes are involved: An excess of hypusine was found in the urine of children and patients with familial hyperlysinemia.

Hypusine was first isolated from bovine brain by Japanese scientists Shiba et al. in 1971.