Deoxyhypusine synthase (DHPS)

Catalyzes the NAD-dependent oxidative cleavage of spermidine and the subsequent transfer of the butylamine moiety of spermidine to the epsilon-amino group of a critical lysine residue of the eIF-5A precursor protein to form the intermediate deoxyhypusine residue. This is the first step of the post- translational modification of that lysine into an unusual amino acid residue named hypusine.

Hypusination is unique to older eIF- 5A factor and is essential for its function. .