Results 11 to 20 of about 10,448 (137)

Electronic Structure, Ionization Potential, and Electron Affinity of the Enzyme Cofactor (6R)-5,6,7,8-Tetrahydrobiopterin in the Gas Phase, Solution, and Protein Environments [PDF]

The Journal of Physical Chemistry B, 2006
(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is a key cofactor involved in the electron transfer to the P(450) heme of nitric oxide synthase. We calculated the electronic structure of the neutral, cationic, and anionic forms of BH(4) in the gas phase, in solution (both dielectric and explicit water), and in the protein environment using density functional ...
Pradip K. Biswas, Jacinto M. Shy, Valentin Gogonea   +2 more
europepmc   +5 more sources

A New Functional Role of 5,6,7,8-tetrahydrobiopterin (BH₄) as an Inhibitor of γ-glutamylcysteine Synthetase (γ-GCS) mRNA Expression

pteridines, 2002
Abstract The effect of the intracellular 5,6,7,8-tetrahydrobiopterin (BH4) on the increased γ-glutamylcysteine synthetase (γ-GCS) mRNA expression induced by nitric oxide (NO) was investigated in RAW264.7 cells. Low doses of nitroprusside (SNP), ranging from 0.1 mM to 0.5 mM, significantly increased the intracellular glutathione levels ...
Maiko Tuchiya, Shuji Kojima, Risa Kurozumi   +2 more
doaj   +4 more sources

The Critical Role of Tetrahydrobiopterin (BH4) Metabolism in Modulating Radiosensitivity: BH4/NOS Axis as an Angel or a Devil [PDF]

Frontiers in Oncology, 2021
Ionizing radiation and radioactive materials have been widely used in industry, medicine, science and military. The efficacy of radiotherapy and adverse effects of normal tissues are closed related to cellular radiosensitivity.
Yang Feng, Yahui Feng, Liming Gu, Pengfei Liu, Jianping Cao, Shuyu Zhang, Shuyu Zhang, Shuyu Zhang   +7 more
doaj   +2 more sources

Inhibition of Ferroptosis by Mesenchymal Stem Cell-Derived Exosomes in Acute Spinal Cord Injury: Role of Nrf2/GCH1/BH4 Axis [PDF]

Neurospine
Objective The therapeutic benefits of exosomes obtained from mesenchymal stem cells (MSCs) in acute spinal cord injury (SCI) have been demonstrated in recent years, but the precise mechanisms remain unknown.
Yixin Chen, Bingfa Li, Jing Quan, Zhe Li, Yan Li, Yinbo Tang   +5 more
doaj   +2 more sources

Age-Related Changes in Brain 6R-L-erythro-5,6,7,8-Tetrahydrobiopterin (R-THBP) and Biogenic Amine Levels in Fischer-344 Rats

pteridines, 1991
T. Noguchi, Yoshihiro Tani, T. Ohno, Tadashi Kanai, T. Ishihara   +4 more
doaj   +4 more sources

Genotypic variants of the tetrahydrobiopterin (BH4) biosynthesis genes in patients with hyperphenylalaninemia from different regions of Iran. [PDF]

Mol Genet Genomic Med
The clinical effect of reported variants is essential for genetic counseling and prenatal diagnosis in the patients' families and significant for the improvement of precision medicine. Abstract Background Hyperphenylalaninemia (HPA) is a metabolic disorder classified into phenylalanine‐4‐hydroxylase (PAH) and non‐PAH deficiency.
Nezhad SRK, Aligoodarzi PN, Rostami G, Shariati G, Galehdari H, Saberi A, Sedaghat A, Sedaghat A, Hamid M.   +8 more
europepmc   +2 more sources

Tetrahydrobiopterin metabolism attenuates ROS generation and radiosensitivity through LDHA S-nitrosylation: novel insight into radiogenic lung injury [PDF]

Experimental and Molecular Medicine
Genotoxic therapy triggers reactive oxygen species (ROS) production and oxidative tissue injury. S-nitrosylation is a selective and reversible posttranslational modification of protein thiols by nitric oxide (NO), and 5,6,7,8-tetrahydrobiopterin (BH4) is
Yang Feng, Yahui Feng, Liming Gu, Wei Mo, Xi Wang, Bin Song, Min Hong, Fenghao Geng, Pei Huang, Hongying Yang, Wei Zhu, Yang Jiao, Qi Zhang, Wei-Qun Ding, Jianping Cao, Shuyu Zhang   +15 more
doaj   +2 more sources

Unveiling Photodegradation and Photosensitization Mechanisms of Unconjugated Pterins

Chemistry – A European Journal, Volume 29, Issue 29, May 22, 2023., 2023
Despite the crucial role of unconjugated pterins in enzymatic processes and the photosensitization of singlet oxygen and other biomolecules, the mechanism underlying the photochemistry of these chromophores is still unclear. With the help of state‐of‐the‐art quantum‐chemical calculations, we shed light into the very fast triplet‐state population, their
Enrique M. Arpa, Inés Corral
wiley   +1 more source

Crystal structure of the ternary complex of Leishmania major pteridine reductase 1 with the cofactor NADP+/NADPH and the substrate folic acid

Acta Crystallographica Section F, Volume 78, Issue 4, Page 170-176, April 2022., 2022
The high‐resolution structure of Leishmania major pteridine reductase 1 in complex with its cofactor NADP+/NADPH and its substrate folic acid is reported. It provides insight into the active‐site rearrangements that occur during the catalytic process.Pteridine reductase 1 (PTR1) is a key enzyme of the folate pathway in protozoan parasites of the genera
Lucia Dello Iacono, Flavio Di Pisa, Stefano Mangani   +2 more
wiley   +1 more source

Evidence for an arginine‐dependent route for the synthesis of NO in the model filamentous fungus Aspergillus nidulans

Environmental Microbiology, Volume 23, Issue 11, Page 6924-6939, November 2021., 2021
Summary Nitric oxide (NO) is a signalling molecule in eukaryotic and prokaryotic organisms. NO levels transiently boost upon induction of conidiation in Aspergillus nidulans. Only one pathway for NO synthesis involving nitrate reductase has been reported in filamentous fungi so far, but this does not satisfy all the NO produced in fungal cells. Here we
Antonio Franco‐Cano, Ana T. Marcos, Joseph Strauss, David Cánovas   +3 more
wiley   +1 more source