label: 4-alpha-hydroxytetrahydrobiopterin dehydratase activity
label_lc: 4-alpha-hydroxytetrahydrobiopterin dehydratase activity
description: "Catalysis of the reaction: (6R)-6-(L-erythro-1,2-dihydroxypropyl)-5,6,7,8-tetrahydro-4a-hydroxypterin = (6R)-6-(L-erythro-1,2-dihydroxypropyl)-7,8-dihydro-6H-pterin + H2O."