Any feedback?
Please rate this page
(ecexplorer.php)
(0/150)

BRENDA support

EC Explorer

EC 2.5.1.46 Details
EC number
2.5.1.46
Accepted name
deoxyhypusine synthase
Reaction
[eIF5A-precursor]-lysine + spermidine = [eIF5A-precursor]-deoxyhypusine + propane-1,3-diamine (overall reaction);;(1a) spermidine + NAD+ = dehydrospermidine + NADH;;(1b) dehydrospermidine + [enzyme]-lysine = N-(4-aminobutylidene)-[enzyme]-lysine + propane-1,3-diamine;;(1c) N-(4-aminobutylidene)-[enzyme]-lysine + [eIF5A-precursor]-lysine = N-(4-aminobutylidene)-[eIF5A-precursor]-lysine + [enzyme]-lysine;;(1d) N-(4-aminobutylidene)-[eIF5A-precursor]-lysine + NADH + H+ = [eIF5A-precursor]-deoxyhypusine + NAD+
Other name(s)
spermidine:eIF5A-lysine 4-aminobutyltransferase (propane-1,3-diamine-forming)
Systematic name
[eIF5A-precursor]-lysine:spermidine 4-aminobutyltransferase (propane-1,3-diamine-forming)
CAS registry number
127069-31-2
Comment
The eukaryotic initiation factor eIF5A contains a hypusine residue that is essential for activity. This enzyme catalyses the first reaction of hypusine formation from one specific lysine residue of the eIF5A precursor. The reaction occurs in four steps: NAD+-dependent dehydrogenation of spermidine (1a), formation of an enzyme-imine intermediate by transfer of the 4-aminobutylidene group from dehydrospermidine to the active site lysine residue (Lys329 for the human enzyme; 1b), transfer of the same 4-aminobutylidene group from the enzyme intermediate to the e1F5A precursor (1c), reduction of the e1F5A-imine intermediate to form a deoxyhypusine residue (1d). Hence the overall reaction is transfer of a 4-aminobutyl group. For the plant enzyme, homospermidine can substitute for spermidine and putrescine can substitute for the lysine residue of the eIF5A precursor. Hypusine is formed from deoxyhypusine by the action of EC 1.14.99.29, deoxyhypusine monooxygenase.
History
provisional version created 1999 as EC 1.1.1.249 deleted 1999, revised and reinstated 2001 as EC 2.5.1.46
EC Tree
2.5.1.12 created 1972, deleted 1976
2.5.1.13 created 1972, deleted 1976
2.5.1.14 created 1972, deleted 1976
2.5.1.37 created 1989, deleted 2004
2.5.1.40 created 1992, deleted 1999