Tetrahydrobiopterin Bh4
Mostrando 13-24 de 30 artigos, teses e dissertações.
-
13. Inducible nitric oxide synthase: identification of amino acid residues essential for dimerization and binding of tetrahydrobiopterin.
Nitric oxide synthases (NOSs) require tetrahydrobiopterin (BH4) for dimerization and NO production. Mutation analysis of mouse inducible NOS (iNOS; NOS2) identified Gly-450 and Ala-453 as critical for NO production, dimer formation, and BH4 binding. Substitutions at five neighboring positions were tolerated, and normal binding of heme, calmodulin, and NADPH
-
14. GTP Cyclohydrolase I Expression, Protein, and Activity Determine Intracellular Tetrahydrobiopterin Levels, Independent of GTP Cyclohydrolase Feedback Regulatory Protein Expression
GTP cyclohydrolase I (GTPCH) is a key enzyme in the synthesis of tetrahydrobiopterin (BH4), a required cofactor for nitricoxide synthases and aromatic amino acid hydroxylases. Alterations of GTPCH activity and BH4 availability play an important role in human disease. GTPCH expression is regulated by inflammatory stimuli, in association with reduced expre
American Society for Biochemistry and Molecular Biology.
-
15. Local tetrahydrobiopterin administration augments cutaneous vasoconstriction in aged humans
Reflex vasoconstriction (VC) is attenuated in aged skin resulting in greater skin blood flow and heat loss during cold exposure. We hypothesized that adrenergic function is compromised due to depletion of tetrahydrobiopterin (BH4), an essential cofactor required for catecholamine synthesis, and therefore local BH4 supplementation would functionally augment r
Blackwell Science Inc.
-
16. Tetrahydrobiopterin Recycling, a Key Determinant of Endothelial Nitric-oxide Synthase-dependent Signaling Pathways in Cultured Vascular Endothelial Cells*S⃞
Tetrahydrobiopterin (BH4) is a key redox-active cofactor in endothelial isoform of NO synthase (eNOS) catalysis and is an important determinant of NO-dependent signaling pathways. BH4 oxidation is observed in vascular cells in the setting of the oxidative stress associated with diabetes. However, the relative roles of de novo BH4 synthesis and BH4 redox
American Society for Biochemistry and Molecular Biology.
-
17. Tetrahydrobiopterin regulates cyclic GMP-dependent electrogenic Cl- secretion in mouse ileum in vitro.
1. Basal electrogenic Cl- secretion, measured as the short-circuit current (Isc), was variable in ileum removed from tetrahydrobiopterin (BH4)-deficient hph-1 mice and wild-type controls in vitro, although values were not significantly different. 2. The basal nitrite release and mucosal cyclic guanosine 3',5'-monophosphate (cyclic GMP) production were simila
-
18. Role of tetrahydrobiopterin in resistance to myocardial ischemia in Brown Norway and Dahl S rats
Previously we showed that Brown Norway (BN/Mcw) rats are more resistant to myocardial ischemia-reperfusion (I/R) injury than Dahl S (SS/Mcw) rats due to increased nitric oxide (·NO) generation secondary to increased heat shock protein 90 (HSP90) association with endothelial nitric oxide synthase (NOS3). Here we determined whether increased resistance to I/R
American Physiological Society.
-
19. Mutations in the Sepiapterin Reductase Gene Cause a Novel Tetrahydrobiopterin-Dependent Monoamine-Neurotransmitter Deficiency without Hyperphenylalaninemia
Classic tetrahydrobiopterin (BH4) deficiencies are characterized by hyperphenylalaninemia and deficiency of monoamine neurotransmitters. In this article, we report two patients with progressive psychomotor retardation, dystonia, severe dopamine and serotonin deficiencies (low levels of 5-hydroxyindoleacetic and homovanillic acids), and abnormal pterin patter
The American Society of Human Genetics.
-
20. The role of phenylalanine in structure–function relationships of phenylalanine hydroxylase revealed by radiation target analysis
The activity of rat liver phenylalanine hydroxylase (PAH; phenylalanine 4-monooxygenase, EC 1.14.16.1) is regulated by interaction with its substrate, phenylalanine, and its coenzyme, BH4 [tetrahydrobiopterin (6R-dihydroxypropyl-l-erythro-5,6,7,8-tetrahydropterin)]. The structural changes accompanying these interactions have been studied by radiation target
The National Academy of Sciences of the USA.
-
21. Endothelium-specific GTP cyclohydrolase I overexpression accelerates refractory wound healing by suppressing oxidative stress in diabetes
Refractory wound is a severe complication that leads to limb amputation in diabetes. Endothelial nitric oxide synthase (eNOS) plays a key role in normal wound repair but is uncoupled in streptozotocin (STZ)-induced type 1 diabetes because of reduced cofactor tetrahydrobiopterin (BH4). We tested the hypothesis that overexpression of GTP cyclohydrolase I (GTPC
American Physiological Society.
-
22. GTP cyclohydrolase I expression is regulated by nitric oxide: role of cyclic AMP
Our previous studies have demonstrated that nitric oxide (NO) leads to nitric oxide synthase (NOS) uncoupling and an increase in NOS-derived superoxide. However, the cause of this uncoupling has not been adequately resolved. The pteridine cofactor tetrahydrobiopterin (BH4) is a critical determinant of endothelial NOS (eNOS) activity and coupling, and GTP cyc
American Physiological Society.
-
23. Inhibition of CDKS by roscovitine suppressed LPS-induced ·NO production through inhibiting NFκB activation and BH4 biosynthesis in macrophages
In inflammatory diseases, tissue damage is critically associated with nitric oxide (·NO) and cytokines, which are overproduced in response to cellular release of endotoxins. Here we investigated the inhibitory effect of roscovitine, a selective inhibitor of cyclin-dependent kinases (CDKs) on ·NO production in mouse macrophages. In RAW264.7 cells, we found
American Physiological Society.
-
24. eNOS uncoupling and endothelial dysfunction in aged vessels
Endothelial nitric oxide synthase (eNOS) uncoupling is a mechanism that leads to endothelial dysfunction. Previously, we reported that shear stress-induced release of nitric oxide in vessels of aged rats was significantly reduced and was accompanied by increased production of superoxide (18, 27). In the present study, we investigated the influence of aging o
American Physiological Society.