Abstract
Biosynthesis of biopterin in the skin of the tadpole, Rana catesbeiana was investigated with guanosine-14 C (U), neopterin-8a-14C, 7, 8-dihydro-neopterin-8a-14C, neopterin-3'-phosphate-8a-14C and 7, 8-dihydro-2-amino-4-hydroxypteridine-8a-14C. It was found that after incubating any of these compounds with tadpole skins radioactive biopterin could be isolated. Neopterin-3'-phosphate-8a-14C and 7, 8-dihydroneopterin were both incorporated into biopterin more effectively than neopterin. Thus, it was postulated that dihydroneopterin-3'-phosphate or its pyrophosphate might be a direct precursor of biopterin.
