title: Biosynthesis of biopterin. Studies on the mechanism of 6-pyruvoyltetrahydropteridine synthase.
abstract: [1'-3H]- and [2'-3H]dihydroneopterin triphosphate (NH2TP) were prepared enzymatically from [4-3H]- and [5-3H]glucose and converted to tetrahydrobiopterin (BH4) by an extract from bovine adrenal medulla. The formation of BH4 from both [1'-3H]- and [2'-3H]-NH2TP proceeds with virtually complete loss of the respective tritium label. The breaking of the CH-bond at C-1' is characterized by a kinetic isotope effect of 2.6 +/- 0.5. A smaller kinetic isotope effect of 1.5 +/- 0.2 was found for the breaking of the CH-bond at C-2'.
authors.affiliation: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Garching, West Germany.
authors.forename: Q
authors.initials: Q
authors.lastname: Le Van
authors.forename: G
authors.initials: G
authors.lastname: Katzenmeier
authors.forename: B
authors.initials: B
authors.lastname: Schwarzkopf
authors.forename: C
authors.initials: C
authors.lastname: Schmid
authors.forename: A
authors.initials: A
authors.lastname: Bacher
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D019798:Neopterin / Q000031:analogs & derivatives; D019761:Phosphorus-Oxygen Lyases; D011621:Pteridines / Q000378:metabolism*; D011622:Pterins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D011621:Pteridines; D011622:Pterins; C013490:dihydroneopterin triphosphate; D001708:Biopterins; D019798:Neopterin; D000429:Alcohol Oxidoreductases; D019761:Phosphorus-Oxygen Lyases; C043497:6-pyruvoyltetrahydropterin synthase; C003402:sapropterin