Catalyzes the hydroxylation of the N(6)-(4-aminobutyl)-L-lysine intermediate to form hypusine, an essential post-translational modification only found in mature eIF-5A factor. [eIF5A protein]-deoxyhypusine + AH2 + O2 = [eIF5A protein]-hypusine + A + H2O Binds 2 Fe(2+) ions per subunit. Optimum pH is 7.5. Active from pH 6 to 10. Protein modification; eIF5A hypusination. Present with 39900 molecules/cell in log phase SD medium. Belongs to the deoxyhypusine hydroxylase family.