2,5 diamino 6 (ribosylamino) 4(3H) pyrimidinone 5' phosphate reductase

2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate reductase (EC 1.1.1.302, 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)⁺ oxidoreductase. This enzyme catalyses the following chemical reaction

2,5-diamino-6-(5-phospho-D-ribitylamino)pyrimidin-4(3H)-one + NAD(P)⁺ ⇌ 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + NAD(P)H + H⁺

The reaction proceeds in the opposite direction. A step in riboflavin biosynthesis, NADPH and NADH functions equally well as a reductant.