17528-72-2 4(1H)-pteridinone, 2-amino-6-(1,2-dihydroxypropyl)-5,6,7,8-tetrahydro- 5,6,7,8-erythro-tetrahydrobiopterin 5,6,7,8-tetra-H-biopterin 5,6,7,8-tetrahydrobiopterin TETRA-H-BIOPTERIN phenylalanine hydroxylase cofactor tetra-hydro-biopterin tetrahydrobiopterin