label: 6-lactoyl-5,6,7,8-tetrahydropterin + NADPH + H(+) => (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin + NADP(+)
label_lc: 6-lactoyl-5,6,7,8-tetrahydropterin + nadph + h(+) => (6r)-l-erythro-5,6,7,8-tetrahydrobiopterin + nadp(+)