Prototropic molecular-zwitterionic tautomerism of xanthine and hypoxanthine: unexpected biological view
نویسندگان
چکیده
منابع مشابه
Xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid as follows
The enzyme is well-suited to carry out the catalysis of these oxidative reactions, containing as it does four redox-active sites: molybdenum, flavin adenine dinucleotide (FAD) and a pair of iron-sulfur centers of the ferredoxin type (Fe2S2). The purine substrates interact with the enzyme at the molybdenum site of xanthine oxidase and oxygen at the flavin site. The two metabolic reactions above ...
متن کاملExperimental and theoretical study of enol-keto prototropic tautomerism and photophysics of azomethine-BODIPY dyads.
In this study we report about two novel azomethine–BODIPY dyads 1 and 2. The two dyads have been, respectively, synthesized by covalent tethering of tautomeric ortho-hydroxy aromatic azomethine moieties including N-salicylideneaniline (SA) and N-naphthlideneaniline (NA) to a BODIPY fluorophore. Both of the two dyads 1 and 2 show enol-imine (OH) structures dominating in the crystalline state. Dy...
متن کاملThe reduction of cytochrome c by hypoxanthine and xanthine oxidase.
Ball, E. G. (1939a). J. biol. Chem. 128, 51. Ball, E. G. (1939b). Cold Spr. Harb. Sym. quant. Biol. 7, 100. Ball, E. G. (1946). J. gen. Phy8iol. 29, 413. Corran, H. S., Dewan, J. G., Gordon, A. H. & Green, D. E. (1939). Biochem. J. 38, 1694. Dixon, M. (1938). Enzymologia, 5, 198. Dixon, M. & Keilin, D. (1936). Proc. roy. Soc. B, 119, 159. Green, D. E., Knox, W. E. & Stumpf, P. K. (1941). J. bio...
متن کاملStudies on Prototropic Tautomerism in Neutral and Monoanionic Forms of Pyrimidines by Nuclear Magnetic Resonance Spectroscopy
NMR methods have been applied to evaluation of prototropic tautomerism, N (1)H ^ N (3) H. in several selected pyrimidines, viz. the neutral forms of isocytosine and 2-alkylthiopyrimidone-4, and the monoanionic forms of uracil, 5-fluorouracil and 4-thiouracil. The predominant tautomeric species of the neutral forms could be estimated only qualitatively from chemical shifts. For the monoanionic f...
متن کاملA kinetic study of hypoxanthine oxidation by milk xanthine oxidase.
The course of the reaction sequence hypoxanthine----xanthine----uric acid catalysed by xanthine:oxygen oxidoreductase from milk was investigated on the basis of u.v. spectra taken during the course of hypoxanthine and xanthine oxidations. It was found that xanthine accumulated in the reaction mixture when hypoxanthine was used as a substrate. The time course of the concentrations of hypoxanthin...
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ژورنال
عنوان ژورنال: Biopolymers and Cell
سال: 2000
ISSN: 0233-7657,1993-6842
DOI: 10.7124/bc.00055f