作者:Andreas Bracher、Wolfgang Eisenreich、Nicholas Schramek、Harald Ritz、Eva Götze、Anja Herrmann、Markus Gütlich、Adelbert Bacher
DOI:10.1074/jbc.273.43.28132
日期:1998.10
GTP cyclohydrolase I catalyzes a ring expansion affording dihydroneopterin triphosphate from GTP. [1',2',3',4',5'-13C5, 2'-2H1]GTP was prepared enzymatically from [U-13C6]glucose for use as enzyme substrate. Multinuclear NMR experiments showed that the reaction catalyzed by GTP cyclohydrolase I involves the release of a proton from C-2' of GTP that is exchanged with the bulk solvent. Subsequently,
GTP环水解酶I催化扩环,从GTP提供二氢蝶呤三磷酸。从[U-13C6]葡萄糖酶促制备[1',2',3',4',5'-13C5,2'-2H1] GTP用作酶底物。多核NMR实验表明,由GTP环水解酶I催化的反应涉及从GTP的C-2'释放质子,并与大量溶剂交换。随后,从本体溶剂中立体定向地引入质子。这符合Amadori重排机制。从溶剂中引入的质子在酶产物中占据pro-7R位置。数据还证实,丙酮酰四氢蝶呤合酶催化的反应导致溶剂质子掺入酶产物的C-6和C-3'位。另一方面,