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7-Substituted pterins in humans with suspected pterin-4a-carbinolamine dehydratase deficiency : mechanism of formation via non-enzymatic transformation from 6-substituted pterins

7-Substituted pterins in humans with suspected pterin-4a-carbinolamine dehydratase deficiency : mechanism of formation via non-enzymatic transformation from 6-substituted pterins

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ADLER, Carmen, Sandro GHISLA, Igor REBRIN, Jan HAAVIK, Claus W. HEIZMANN, Nenad BLAU, Thomas KUSTER, Hans-Christoph CURTIUS, 1992. 7-Substituted pterins in humans with suspected pterin-4a-carbinolamine dehydratase deficiency : mechanism of formation via non-enzymatic transformation from 6-substituted pterins. In: European Journal of Biochemistry. 208(1), pp. 139-144. ISSN 0014-2956. eISSN 1432-1033. Available under: doi: 10.1111/j.1432-1033.1992.tb17167.x

@article{Adler19927Subs-7681, title={7-Substituted pterins in humans with suspected pterin-4a-carbinolamine dehydratase deficiency : mechanism of formation via non-enzymatic transformation from 6-substituted pterins}, year={1992}, doi={10.1111/j.1432-1033.1992.tb17167.x}, number={1}, volume={208}, issn={0014-2956}, journal={European Journal of Biochemistry}, pages={139--144}, author={Adler, Carmen and Ghisla, Sandro and Rebrin, Igor and Haavik, Jan and Heizmann, Claus W. and Blau, Nenad and Kuster, Thomas and Curtius, Hans-Christoph} }

deposit-license Blau, Nenad Curtius, Hans-Christoph Rebrin, Igor Ghisla, Sandro Haavik, Jan 1992 2011-03-24T17:36:20Z A recently described new form of hyperphenylalaninemia is characterized by the excretion of 7-substituted isomers of biopterin and neopterin and 7-oxo-biopterin in the urine of patients. It has been shown that the 7-substituted isomers of biopterin and neopterin derive from L-tetrahydrobiopterin and D-tetrahydroneopterin and are formed during hydroxylation of phenylalanine to tyrosine with rat liver dehydratase-free phenylalanine hydroxylase.<br />We have now obtained identical results using human phenylalanine hydroxylase. The identity of the pterin formed in vitro and derived from L-tetrahydrobiopterin as 7-(1',2'-dihydroxypropyl)pterin was proven by gas-chromatography mass spectrometry. Tetrahydroneopterin and 6-hydroxymethyltetrahydropterin also are converted to their corresponding 7-substituted isomers and serve as cofactors in the phenylalanine hydroxylase reaction. Dihydroneopterin is converted by dihydrofolate reductase to the tetrahydro form which is biologically active as a cofactor for the aromatic amino acid monooxygenases. The 6-substituted pterin to 7-substituted pterin conversion occurs in the absence of pterin-4a-carbinolamine dehydratase and is shown to be a nonenzymatic process. 7-Tetrahydrobiopterin is both a substrate (cofactor) and a competitive inhibitor with 6-tetrahydrobiopterin (Ki ≈ 8 μM) in the phenylalanine hydroxylase reaction. For the first time, the formation of 7-substituted pterins from their 6-substituted isomers has been demonstrated with tyrosine hydroxylase, another important mammalian enzyme which functions in the hydroxylation of phenylalanine and tyrosine. Kuster, Thomas Ghisla, Sandro eng Adler, Carmen application/pdf First publ. in: European Journal of Biochemistry 208 (1992), 1, pp. 139-144 Adler, Carmen Blau, Nenad Kuster, Thomas 7-Substituted pterins in humans with suspected pterin-4a-carbinolamine dehydratase deficiency : mechanism of formation via non-enzymatic transformation from 6-substituted pterins Rebrin, Igor Haavik, Jan Heizmann, Claus W. Heizmann, Claus W. Curtius, Hans-Christoph 2011-03-24T17:36:20Z

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