Histidine 179 Mutants of GTP Cyclohydrolase I Catalyze the Formation of 2-Amino-5-formylamino-6-ribofuranosylamino-4(3H)-pyrimidinone Triphosphate
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چکیده
منابع مشابه
Ring opening is not rate-limiting in the GTP cyclohydrolase I reaction.
GTP cyclohydrolase I catalyzes a mechanistically complex ring expansion affording dihydroneopterin triphosphate and formate from GTP. Single turnover quenched flow experiments were performed with the recombinant enzyme from Escherichia coli. The consumption of GTP and the formation of 5-formylamino-6-ribosylamino-2-amino-4(3H)-pyrimidinone triphosphate, formate, and dihydroneopterin triphosphat...
متن کاملEnzymic characterization of Bacillus subtilis GTP cyclohydrolase I. Evidence for a chemical dephosphorylation of dihydroneopterin triphosphate.
GTP cyclohydrolase I catalyses the first committing step in the biosynthesis of the pterin moiety of folic acid: conversion of GTP to dihydroneopterin triphosphate. GTP cyclohydrolase I of Bacillus subtilis was purified to homogeneity and shown to have a homo-octameric structure. The enzyme had an apparent Km for GTP of 4 microM and, in the absence of cations, a Vmax. of 80 nmol/min per mg of p...
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15 صفحه اولThe Protein Partners of GTP Cyclohydrolase I in Rat Organs
OBJECTIVE GTP cyclohydrolase I (GCH1) is the rate-limiting enzyme for tetrahydrobiopterin biosynthesis and has been shown to be a promising therapeutic target in ischemic heart disease, hypertension, atherosclerosis and diabetes. The endogenous GCH1-interacting partners have not been identified. Here, we determined endogenous GCH1-interacting proteins in rat. METHODS AND RESULTS A pulldown an...
متن کاملBiochemical characterization of oligomerization of Escherichia coli GTP cyclohydrolase I.
GTP cyclohydrolase I (E.C. 3.5.4.16) is a homodecameric protein that catalyzes the conversion of GTP to 7,8- dihydroneopterin triphosphate (H(2)NTP), the initial step in the biosynthesis of pteridines. It was proposed that the enzyme complex could be composed of a dimer of two pentamers, or a pentamer of tightly associated dimers; then the active site of the enzyme was located at the interface ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1999
ISSN: 0021-9258
DOI: 10.1074/jbc.274.24.16727