Deoxyhypusine monooxygenase

In enzymology, a deoxyhypusine monooxygenase (EC 1.14.99.29) is an enzyme that catalyzes the chemical reaction The 3 substrates of this enzyme are a protein-bound N6-(4-aminobutyl)-L-lysine, an electron acceptor AH2, and O2, and its 3 products are protein-bound N6-[(R)-4-amino-2-hydroxybutyl]-L-lysine, the reduction product A, and H2O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen.

The systematic name of this enzyme class is deoxyhypusine,hydrogen-donor:oxygen oxidoreductase (2-hydroxylating).

The HUGO symbol for human gene and protein is DOHH, the full name is deoxyhypusine hydroxylase, and there are orthologs in other mammals.

The difference in case is just a meaningless historical artifact.