Results 131 to 140 of about 1,078 (162)
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Talanta, 2008
Abstract An off-line photoirradiation LC fluorimetric method to determine tetrahydrobiopterin (BH4), by photogeneration of biopterin (BIO), is described, as an alternative way to the chemical oxidation procedure. To minimize the uncontrolled BH4 oxidation, due to environmental oxygen, an antioxidant, dithiothreitol (DTT), was used. The acidity of the
A. Muñoz de la Peña +3 more
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Abstract An off-line photoirradiation LC fluorimetric method to determine tetrahydrobiopterin (BH4), by photogeneration of biopterin (BIO), is described, as an alternative way to the chemical oxidation procedure. To minimize the uncontrolled BH4 oxidation, due to environmental oxygen, an antioxidant, dithiothreitol (DTT), was used. The acidity of the
A. Muñoz de la Peña +3 more
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Quantitation of total biopterin and tetrahydrobiopterin in plasma
Clinical Biochemistry, 2007To develop a reliable method for the determination of tetrahydrobiopterin and total biopterin in plasma.Modifications include blood collection and handling procedures.Collection of blood in the presence of 0.1% (w/v) dithiothreitol and waiting for 2-3 h before centrifugation are optimal for adequate quantitation of both pterins.For a reliable ...
Ans Voskuilen-Kooijman, Durk Fekkes
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Pteridine, LXXV. Synthese und Eigenschaften von Biopterin und Biopterin‐Analogen
Liebigs Annalen der Chemie, 1984AbstractDie Synthese von Biopterin (6), seinem 2‐N,N‐Dimethyl‐ (8) und 4‐ Thioxo‐Derivat (19) sowie von Biolumazin (7) wird beschrieben. Durch Umsetzung von Biopterin mit α‐Acetoxyisobuttersäurechlorid läß sich die Seitenkette zu 6‐(L‐threo‐2‐Acetoxy‐1‐chlorpropyl)pterin (10) modifizieren, das als Ausgangsmaterial fär weitere Derivatisierungen dienen ...
Mathias Kappel +2 more
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Screening for Biopterin Disorders in PKU
Pediatrics, 1980It is now recognized (Pediatrics 65:806, 1980) that a small proportion of cases of phenylketonuria (PKU) may be due to abnormalities in the metabolism of biopterin. These cases do not respond to the restriction of dietary phenylalanine, but may be benefited by neurotransmitter replacement therapy. A specific diagnosis is therefore desirable.
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The Origin of Red Blood Cell Biopterin
Molecular Genetics and Metabolism, 1998Data are presented to support the hypothesis that the biopterin content of red blood cells arises during erythropoiesis. Only when the plasma concentration rises above the erythrocyte concentration of biopterin is there likely to be diffusion into the cell.
R. J. Leeming, S.K. Hall, Anne Green
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Cytotoxicity of 6-Biopterin to Human Melanocytes
Biochemical and Biophysical Research Communications, 1994(6R)5,6,7,8 tetrahydrobiopterin (6-BH4) is an important cofactor in the regulation of melanogenesis in melanocytes, where it controls: (a) the supply of L-tyrosine from L-phenylalanine via phenylalanine hydroxylase, and (b) regulates directly dopaquinone formation from L-tyrosine via tyrosinase.
John M. Wood +5 more
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Synthesis of biopterin and related pterin glycosides
IUBMB Life, 2013AbstractCertain pterins having a hydroxyalkyl side chain at C‐6 have been found as glycosidic forms in certain prokaryotes, such as 2′‐O‐(α‐D‐glucopyranosyl)biopterin from various kinds of cyanobacteria, and limipterin from a green sulfur photosynthetic bacterium.
Hiroshi Yamamoto, Tadashi Hanaya
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Biopterin cofactor and monoamine-synthesizing monooxygenases
Neurochemistry International, 1983The activities of three pterin-requiring monooxygenases, phenylalanine hydroxylase, tyrosine hydroxylase and tryptophan hydroxylase, are regulated by the level of the pterin cofactor, (6R)- l -erythro- tetrahydrobiopterin , which is synthesized from guanosine triphosphate (GTP).
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Diastereomers of Neopterin and Biopterin in Human Urine
Biological Chemistry Hoppe-Seyler, 1992A new pteridine compound, named umanopterin, was isolated from human urine both of cancer patients and non-cancer controls. The structure was confirmed to be 2-amino-4(3H)-oxo-6-[(1'R,2'R)-1',2',3'-trihydroxypropyl]pteridine , a diastereomer of neopterin.
Keisuke Fujita +4 more
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Biopterin metabolism in patients with malignant syndrome
Parkinsonism & Related Disorders, 2003We examined the autopsied brains of two parkinsonian patients who had malignant syndrome (MS). Neopterin and biopterin contents, and GTP cyclohydrolase I activity were measured in various region of the brain. We found relatively higher GTP cyclohydrolase I activities in the hypothalamus compared with other regions of the brain from patients with MS ...
H. Ichinose +7 more
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