Sepiapterin reductase

Sepiapterin reductase is an is_associated_with::enzyme that in humans is encoded by the SPR is_associated_with::gene.

Function
Sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase; EC 1.1.1.153) catalyzes the NADPH-dependent reduction of various carbonyl substances, including derivatives of pteridines, and belongs to a group of enzymes called aldo-keto reductases. SPR plays an important role in the biosynthesis of is_associated_with::tetrahydrobiopterin.

Reaction
Sepiapterin reductase (SPR) catalyzes the is_associated_with::chemical reaction

L-erythro-7,8-dihydrobiopterin + NADP+ $$\rightleftharpoons$$ sepiapterin + NADPH + H+

Thus, the two substrates of this enzyme are is_associated_with::L-erythro-7,8-dihydrobiopterin and NADP+, whereas its three products are is_associated_with::sepiapterin, NADPH, and a single is_associated_with::hydrogen ion (H+).

This enzyme belongs to the family of is_associated_with::oxidoreductases, to be specific, those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The is_associated_with::systematic name of this enzyme class is 7,8-dihydrobiopterin:NADP+ oxidoreductase. This enzyme participates in is_associated_with::folate biosynthesis.