title: Intermediates in the enzymic synthesis of tetrahydrobiopterin in Drosophila melanogaster.
abstract: 9 partially purified enzyme (Enzyme A) from Drosophila melanogaster Aatalyzes the conversion of 7,8- dihydroneopterin triphosphate to a compound that, from its ultraviolet absorption spectrum and other characteristics, appears to be 6- pyruvoyl -tetrahydropterin. This product can be converted to 6-lactoyl-tetrahydropterin in the presence of another partially purified enzyme (Enzyme B) and NADPH, and to 5,6,7,8-tetrahydrobiopterin in the presence of a third enzyme preparation (biopterin synthase) and NADPH. The enzymically-produced 6-lactoyl-tetrahydropterin, when exposed to air, is oxidized nonenzymically to sepiapterin (6-lactoyl-7,8- dihydropterin ). The results indicate that although 6-lactoyl-tetrahydropterin can be converted enzymically to tetrahydrobiopterin, neither it nor sepiapterin is an obligate intermediate in the conversion of 7,8- dihydroneopterin triphosphate to tetrahydrobiopterin.
mesh_terms: D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000378:metabolism; D001711:Biotransformation; D002384:Catalysis; D004331:Drosophila melanogaster / Q000201:enzymology / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D008274:Magnesium / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D019798:Neopterin / Q000031:analogs & derivatives; D011621:Pteridines / Q000096:biosynthesis* / Q000378:metabolism; D011622:Pterins
chemical_list: D011621:Pteridines; D011622:Pterins; C013490:dihydroneopterin triphosphate; D001708:Biopterins; C041361:6-lactoyltetrahydropterin; D009249:NADP; D019798:Neopterin; D004492:Edetic Acid; C016727:sepiapterin; C003402:sapropterin; D008274:Magnesium