Results 181 to 190 of about 4,605 (211)

Studies on GTP Cyclohydrolase I of Escherichia Coli

1993
GTP cyclohydrolase I (EC 3.5.4.16) has been obtained from Escherichia coli wild type cells by affinity chromatography.1,2 The gene coding for the enzyme from E. coli has been cloned and sequenced3,4 and has been mapped at 2251 kb of the physical map of the E.
Cornelia Schmid, Winfried Meining, Sevil Weinkauf, Luis Bachmann, Harald Ritz, Sabine Eberhardt, Wolfgang Gimbel, Thomas Werner, Hans-Werner Lahm, Herbert Nar, Adelbert Bacher   +10 more
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Disruption of the GTP-Cyclohydrolase I Gene InSaccharomyces cerevisiae

Biochemical and Biophysical Research Communications, 1996
GTP-cyclohydrolase I is the first enzyme in the biosynthetic pathway leading to folic acid and tetrahydrobiopterin. We determined the complete sequence of the GTP-cyclohydrolase I gene from the yeast Saccharomyces cerevisiae. The gene, which is located in the subtelomeric region of the right arm of chromosome VII, gives a major transcript of about 1000
V, Nardese, M, Gütlich, A, Brambilla, M L, Carbone   +3 more
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Down-regulation of GTP cyclohydrolase I and tetrahydrobiopterin by melatonin

NeuroReport, 2000
Tetrahydrobiopterin (BH4) is spontaneously released and extracellularly exerts a toxic effect preferentially on catecholamine cells. Its synthesis rate is mainly determined by the activity of the enzyme GTP cyclohydrolase I (GTPCH). In the present study, role of melatonin BH4 synthesis was determined using the catecholaminergic CATH.a cells.
Y J, Jang, H N, Hong, J D, Lee, O, Hwang
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Mutations in GTP-cyclohydrolase I gene and vitiligo

The Lancet, 1997
Sporadic and familial cases of vitiligo, some of them associated with autoimmune endocrine disorders, have been described. Although an autosomal dominant inheritance with low penetrance is suspected, no genetic locus has yet been identified. It has been shown that tetrahydrobiopterin regulates melanin biosynthesis, and that patients with vitiligo have ...
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Regulation of GTP Cyclohydrolase I by Estrogen

2002
Estrogens are well known for their protective effects on the cardiovascular system (1,2). Activation of estrogen receptors which have been identified in endothelial and vascular smooth muscle cells leads to changes in gene expression and alterations in cellular function (3,4).
Christian Hesslinger, Z. Chen, Amrita Ahluwalia, David L. Selwood, Patrick Vallance, Josef Pfeilschifter, Aroon D. Hingorani   +6 more
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Multiple mRNA forms of human GTP cyclohydrolase I

Biochemical and Biophysical Research Communications, 1992
To isolate full length cDNA clones encoding human GTP cyclohydrolase I, the first and rate-limiting enzyme in tetrahydrobiopterin biosynthesis, a cDNA library generated from human liver was screened by plaque hybridization. Analysis of the clones, hybridized with rat cDNA fragment, by restriction mapping and partial sequencing showed the existence of ...
A. Togari, H. Ichinose, S. Matsumoto, K. Fujita, T. Nagatsu   +4 more
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Detection and Quantification of GTP Cyclohydrolase I m RNA

1993
There is accumulating evidence that H4biopterin is synthesized in cells which do not depend on H4biopterin cofactor but undergo cytokine directed proliferation1. In this case, H4biopterin has a function which is apparently unrelated to its known cofactor role.
M, Gütlich, K, Schott, T, Werner, A, Bacher, I, Ziegler   +4 more
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Feedback Regulation Mechanisms for the Control of GTP Cyclohydrolase I Activity

Science, 1993
Guanosine triphosphate (GTP) cyclohydrolase I, the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin (BH 4 ), is subject to feedback inhibition by BH 4 , a cofactor for phenylalanine hydroxylase. Inhibition was found to depend specifically on BH 4 and the
T, Harada, H, Kagamiyama, K, Hatakeyama
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Studies on the Reaction Mechanism of GTP Cyclohydrolase I

2002
GTP cyclohydrolase I catalyzes a ring expansion affording dihydroneopterin triphosphate from GTP (1, 2). The reaction involves the release of C-8 of GTP as formate. The catalytic domain of the human enzyme shows 37% identity with that of Escherichia coli.
Nicholas Schramek, Andreas Bracher, Gerd Bader, Markus Fischer, Günter Auerbach, Markus Gütlich, Wolfgang Eisenreich, Robert Huber, Adelbert Bacher   +8 more
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Human liver GTP cyclohydrolase I: purification and some properties

Biochimie, 1989
Human liver guanosine triphosphate (GTP) cyclohydrolase I has been purified more than 1,700-fold to what appears to be homogeneity. The active enzyme complex has an estimated molecular weight of 453,000 +/- 11,500 by gel filtration chromatography. It consists of a polypeptide of 149,000 +/- 4,000 mol wt by SDS-polyacrylamide gel electrophoresis.
R S, Shen, A, Alam, Y X, Zhang
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