Hypusinylation Authored: Johansson, HE, 2007-11-28 23:26:30 Cytosolic eIF5A undergoes a unique two-step post-translational modification at Lys 50 via deoxyhypusine (Dhp) to hypusine (Hyp). In the first step deoxyhypusine synthase transfers the aminobutyl group of spermidine to the epsilon-amino group of lysine 50, using NAD+ as a cofactor. Hydroxylation of the C2 of the newly added moiety in the second step is catalyzed by deoxyhypusine hydroxylase/monooxygenase with molecular oxygen as the source. The molecular function of eIF5A is unknown, but the protein is required for viability in eukaryotic cells and its normal function requires hypusinylation. eIF5A is the only protein known to undergo hypusinylation (Park 2006). Edited: D'Eustachio, P, 2007-11-28 23:33:46 GENE ONTOLOGYGO:0008612 Hypusine synthesis from eIF5A-lysine Pubmed16452303 Reactome Database ID Release 43204626 Reactome, http://www.reactome.org ReactomeREACT_12469 Reviewed: Jassal, B, 2008-01-28 15:51:00 PathwayStep3074 PathwayStep3073 PathwayStep3075 EIF5A + spermidine <=> EIF5A(Dhp) + 1,3-diaminopropane EIF5A(Dhp) + 1,3-diaminopropane <=> EIF5A + spermidine EIF5A(Dhp) + O2 => EIF5A(Hyp)