(6R)-L-erythro-6,7-dihydrobiopterin + NADH + H(+) => (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + NAD(+)
(6r)-l-erythro-6,7-dihydrobiopterin + nadh + h(+) => (6r)-l-erythro-5,6,7,8-tetrahydrobiopterin + nad(+)
(6R)-L-erythro-6,7-dihydrobiopterin + NADH + H(+) => (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + NAD(+)
(6r)-l-erythro-6,7-dihydrobiopterin + nadh + h(+) => (6r)-l-erythro-5,6,7,8-tetrahydrobiopterin + nad(+)