Fostering real social contracts - Hermann Bacher and WOTR

Ziegler, Rafael; Henkel, Marianne

doi:10.4337/9781783471317.00013

Cited by 1 publication

(4 citation statements)

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“…Protein solutions were dialysed against 50 mM Tris/HC1, pH 8.0, and were incubated at 37°C with 0.5 mM GTP as described previously [14]. GTP cyclohydrolase I activity was assayed (i) by the formation of dihydroneopterin triphosphate which was oxidized by acidic iodine and monitored by h.p.l.c.…”

Section: Determination Of Gtp Cyclohydrolase I Activitymentioning

confidence: 99%

“…GTP cyclohydrolase I activity was assayed (i) by the formation of dihydroneopterin triphosphate which was oxidized by acidic iodine and monitored by h.p.l.c. [14] or (ii) by the release of formic acid from [8-14C]GTP (Amersham, Braunschweig, Germany) as described by Fukushima et al [43].…”

Section: Determination Of Gtp Cyclohydrolase I Activitymentioning

confidence: 99%

“…It is synthesized in all tissues competent for phenylalanine degradation or neurotransmitter biosynthesis, such as liver, brain or adrenal medulla [12]. In macrophages [13] or in primed T cells [14], the accumulation of neopterin and BH4 is selectively triggered by IFN-y. IFN-y also appears to control BH4 formation in NO-producing endothelial cells or macrophages [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…The IFN-y-mediated up-regulation of activity in monocytes/ macrophages or in primed T cells [14] correlated with increases in the steady-state mRNA levels specific for GTP cyclohydrolase I [22]. A post-translational control of GTP cyclohydrolase I activity was shown in rat liver, where BH4 acts as a feedback regulator via a regulatory protein [23].…”

Section: Introductionmentioning

confidence: 99%

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Human GTP cyclohydrolase I: only one out of three cDNA isoforms gives rise to the active enzyme

Gütlich¹,

Jaeger

Rücknagel³

et al. 1994

Biochemical Journal

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GTP cyclohydrolase I catalyses the first and rate-limiting step of tetrahydrobiopterin biosynthesis. Its expression is regulated by interferon-gamma or kit ligand in a tissue-specific manner. Three different cDNA forms have been reported for human GTP cyclohydrolase I [Togari, Ichinose, Matsumoto, Fujita and Nagatsu (1992) Biochem. Biophys. Res. Commun. 187, 359-365]. We have isolated, from a human liver cDNA library, two clones which contained inserts identical with two of the cDNAs reported by Togari et al. (1992). The three open reading frames corresponding to all reported cDNA sequences were expressed in Escherichia coli. Only the recombinant protein corresponding to the longest reading frame catalysed the conversion of GTP into dihydroneopterin triphosphate. The proteins corresponding to the shorter reading frames failed to catalyse not only the generation of dihydroneopterin triphosphate but also the release of formate from GTP, an intermediate step of the reaction. Recombinant human GTP cyclohydrolase I showed sigmoidal substrate kinetics and maximum activity at 60 degrees C. These findings are well in line with the published properties of the enzyme isolated from rat liver. The data indicate that cytokine-mediated induction of GTP cyclohydrolase I is not due to the expression of enzyme isoforms.

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Section: Determination Of Gtp Cyclohydrolase I Activitymentioning

confidence: 99%

Section: Determination Of Gtp Cyclohydrolase I Activitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations