Diaminohydroxyphosphoribosylaminopyrimidine deaminase

In enzymology, a diaminohydroxyphosphoribosylaminopyrimidine deaminase is an enzyme that catalyzes the chemical reaction


 * 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine + H2O $$\rightleftharpoons$$ 5-amino-6-(5-phosphoribosylamino)uracil + NH3

Thus, the two substrates of this enzyme are 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine and H2O, whereas its two products are 5-amino-6-(5-phosphoribosylamino)uracil and NH3.

This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. The systematic name of this enzyme class is 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine 2-aminohydrolase. This enzyme participates in riboflavin metabolism.

Structural studies
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes, , , , , and.