title: Biosynthesis of pteridines. Stopped-flow kinetic analysis of GTP cyclohydrolase I.
abstract: GTP cyclohydrolase I catalyzes a mechanistically complex ring expansion affording dihydroneopterin triphosphate from GTP. The inherently slow enzyme reaction was studied under single turnover conditions monitored by multiwavelength ultraviolet spectroscopy. The spectroscopic data array was subjected to singular value decomposition and thereby shown to comprise six significant linearly independent optical processes. The data were fitted to a model of six consecutive unimolecular reaction steps where the first was considered to be reversible. The rate-limiting step was shown to occur rather late in the reaction sequence.
authors: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
authors: A
authors: A
authors: Bracher
authors: N
authors: N
authors: Schramek
authors: A
authors: A
authors: Bacher
mesh_terms: D002384:Catalysis; D006136:GTP Cyclohydrolase / Q000737:chemistry* / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008956:Models, Chemical; D010777:Photochemistry; D011621:Pteridines / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011621:Pteridines; D006160:Guanosine Triphosphate; D006136:GTP Cyclohydrolase