Deoxyhypusine synthase is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ...

that in humans is encoded by the ''DHPS''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ...

. The unusual amino acid hypusine is formed posttranslationally and is only found in a single cellular protein, eukaryotic translation initiation factor 5A ( EIF5A, EIF5A2). In the first step of hypusine biosynthesis, deoxyhypusine synthase catalyzes the NAD-dependent transfer of the butylamine moiety of

spermidine Spermidine is a polyamine compound () found in ribosomes and living tissues and having various metabolic functions within organisms. It was originally isolated from semen. Function Spermidine is an aliphatic polyamine. Spermidine synthase (SPDS) ...

to the epsilon-amino group of a specific

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −CO ...

residue of the EIF5A precursor protein to form the intermediate deoxyhypusine residue. This gene consists of nine

exons An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequenc ...

spanning 6.6 kb. Three transcript variants have been isolated. However, only transcript variant 1 encodes an active protein. The shorter variants may act as modulating factors of DHPS activity.

References

Further reading