2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate reductase (, 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate reductase, MjaRED, MJ0671 (gene)) is an enzyme with systematic name 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one:NAD(P)<sup>+</sup> oxidoreductase. This enzyme catalyses the following chemical reaction
The reaction proceeds in the opposite direction. A step in riboflavin biosynthesis, NADPH and NADH functions equally well as a reductant.