Formation of reduced nicotinamide adenine dinucleotide peroxide.

Bernofsky, Carl; Wanda, Soo-Young

doi:10.1016/s0021-9258(18)34502-2

Cited by 42 publications

(27 citation statements)

References 28 publications

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“…In a later paper, the same authors demonstrated the presence of H # O # in their phosphate buffers [50]. Taken together, the results became consistent with previous studies indicating that the peroxidasecatalysed oxidation of NAD(P)H by O # required small amounts of H # O # [36][37][38], which could be present in aerobically prepared solutions owing to a slow autoxidation process [51]. In the present study this disagreement was avoided by the use of freshly prepared NADPH solutions.…”

Section: Discussionsupporting

confidence: 91%

NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase

Auchère

Capeillère‐Blandin

1999

Biochem. J.

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The reinvestigation of the kinetics of myeloperoxidase (MPO) activity with the use of NADPH as a probe has allowed us to determine the effects of H(2)O(2), Cl(-) ion and pH on the MPO-dependent production of HOCl. The chlorination rate of NADPH did not depend on NADPH concentration and was entirely related to the rate of production of HOCl by MPO. The overall oxidation of NADPH occurred similarly in the absence of O(2) and was insensitive to scavengers of the superoxide radical anion. Experiments performed on the direct oxidation of NADPH by MPO in the presence and the absence of H(2)O(2) showed that neither the rate nor the stoichiometry of the reaction could interfere in the NADPH oxidation process involved in the steady-state chlorination cycle. The oxidation of NADPH was characterized by a decrease in the A(339) of the reduced nicotinamide with the concomitant appearance of a new chromophore with absorbance maximum at 274 nm, characterized by isosbestic points at 300 and 238 nm. The reaction product did not possess any enzymic properties with dehydrogenases and led to a metabolite other than NADP(+). Its amount accounted for a stoichiometric conversion of H(2)O(2) into HOCl. Analyses of the NADPH reaction allowed the determination of both kinetic (k(cat) and K(m)) and thermodynamic (K(d)) parameters. When the values of kinetic parameters were compared with previously published ones, the main discrepancy was found with data obtained with the chlorination of monochlorodimedon and a better agreement with diethanolchloramine formation or H(2)O(2) consumption. Variations in the extent of NADPH oxidation with Cl(-) concentration enabled us to determine the dissociation constant for the enzyme-Cl(-) complex. In the course of titration studies, the spectral properties of NADPH reacting with either HOCl or the MPO/H(2)O(2)/Cl(-) system were quantitatively similar in terms of stoichiometry and absorbance coefficient and thus led to identical chlorinated products. However, no spectral modification occurred with NADP(+) and adenine nucleotide analogues under the same conditions. A quantitative comparison of difference spectra obtained with NADPH and NMNH indicated that chlorination occurred on the nicotinamide part of the molecule.

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Section: Discussionsupporting

confidence: 91%

NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase

Auchère

Capeillère‐Blandin

1999

Biochem. J.

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“…Dihydroorotate dehydrogenase assays were performed at 30 °C in potassium phosphate buffer, (100 mM, pH 7.5) using a Hitachi U-3010 UV/Visible spectrophotometer (Chiyoda, Tokyo, Japan). Formation of orotate or reduction of NAD(P) + was monitored by measuring absorbance at 300 nm (ε = 3.05 mM −1 cm −1 ; [ 14 ]) or 340 nm (ε = 6.22 mM −1 cm −1 ; [ 107 ]) respectively, upon addition of 1 mM dihydroorotate to a temperature-equilibrated reaction mixture containing buffer, cell extract and/or either of the electron acceptors fumarate (1 mM), decylubiquinone (Q D , 0.1 mM, dissolved in dimethylsulfoxide), nicotinamide adenine dinucleotide (NAD + , 1 mM), nicotinamine adenine dinucleotide phosphate (NADP + , 1 mM), flavine adenine dinucleotide (FAD, 20 μM), flavin mononucleotide (FMN, 20 μM) or the artificial electron acceptor phenazine methosulfate (PMS, 0.1 mM). Enzyme assays were performed on two separately prepared cell extracts.…”

Section: Methodsmentioning

confidence: 99%

Class-II dihydroorotate dehydrogenases from three phylogenetically distant fungi support anaerobic pyrimidine biosynthesis

Bouwknegt

Koster

Vos

et al. 2021

Fungal Biol Biotechnol

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Background In most fungi, quinone-dependent Class-II dihydroorotate dehydrogenases (DHODs) are essential for pyrimidine biosynthesis. Coupling of these Class-II DHODHs to mitochondrial respiration makes their in vivo activity dependent on oxygen availability. Saccharomyces cerevisiae and closely related yeast species harbor a cytosolic Class-I DHOD (Ura1) that uses fumarate as electron acceptor and thereby enables anaerobic pyrimidine synthesis. Here, we investigate DHODs from three fungi (the Neocallimastigomycete Anaeromyces robustus and the yeasts Schizosaccharomyces japonicus and Dekkera bruxellensis) that can grow anaerobically but, based on genome analysis, only harbor a Class-II DHOD. Results Heterologous expression of putative Class-II DHOD-encoding genes from fungi capable of anaerobic, pyrimidine-prototrophic growth (Arura9, SjURA9, DbURA9) in an S. cerevisiae ura1Δ strain supported aerobic as well as anaerobic pyrimidine prototrophy. A strain expressing DbURA9 showed delayed anaerobic growth without pyrimidine supplementation. Adapted faster growing DbURA9-expressing strains showed mutations in FUM1, which encodes fumarase. GFP-tagged SjUra9 and DbUra9 were localized to S. cerevisiae mitochondria, while ArUra9, whose sequence lacked a mitochondrial targeting sequence, was localized to the yeast cytosol. Experiments with cell extracts showed that ArUra9 used free FAD and FMN as electron acceptors. Expression of SjURA9 in S. cerevisiae reproducibly led to loss of respiratory competence and mitochondrial DNA. A cysteine residue (C265 in SjUra9) in the active sites of all three anaerobically active Ura9 orthologs was shown to be essential for anaerobic activity of SjUra9 but not of ArUra9. Conclusions Activity of fungal Class-II DHODs was long thought to be dependent on an active respiratory chain, which in most fungi requires the presence of oxygen. By heterologous expression experiments in S. cerevisiae, this study shows that phylogenetically distant fungi independently evolved Class-II dihydroorotate dehydrogenases that enable anaerobic pyrimidine biosynthesis. Further structure–function studies are required to understand the mechanistic basis for the anaerobic activity of Class-II DHODs and an observed loss of respiratory competence in S. cerevisiae strains expressing an anaerobically active DHOD from Sch. japonicus.

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“…The deterministic route for the subsequent electrochemical reduction of NAD + , which depends on several experimental factors such as the time scale of the experiment, the presence of competing adsorption, continues stepwise reaction pathways accompanying the free radical form NAD + intermediates, and so on (45). As shown in Scheme 3, two possible expected routes can complete the electrochemical reduction of the radical form of NAD + ; (I) protonation of free radical intermediates to form monomers and (II) radical coupling to form dimers (46).…”

Section: Resultsmentioning

confidence: 99%

Highly Efficient S‐g‐CN/Mo‐368 Catalyst for Synergistically NADH Regeneration Under Solar Light

Gupta

Yadav

et al. 2021

Photochem & Photobiology

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Sulfur‐doped graphitic carbon nitride (S‐g‐CN) has gained significant attention in recent years. Sulfur‐doped graphitic carbon nitride (S‐g‐CN) is a promising metal‐free photocatalyst because of its band orientation, natural abundance and groundwork. Improved photocatalytic activity of S‐g‐CN material for solar chemical production persists a hot yet challenging problem. Herein, we provide an adaptable method for the synthesis of S‐g‐CN nanocomposite decorated with the moiety of giant polyoxometalate (S‐g‐CN/Mo‐368) that subsequently showed highly efficient photocatalytic activity. The as‐synthesized S‐g‐CN/Mo‐368 as a recyclable artificial photocatalyst revealed excellent activity for solar chemical production, that is nicotinamide adenine dinucleotide (NADH) regeneration under visible light. The immobilized Mo‐368 on the S‐g‐CN surface increased the visible light adsorption capacity of the S‐g‐CN/Mo‐368 photocatalyst. The visible light absorption activity, morphology, element compositions, particle size and zeta potential of S‐g‐CN powder and S‐g‐CN/Mo‐368 were thoroughly investigated. From the application point of view, S‐g‐CN/Mo‐368 was applied to determine the solar chemical production (i.e. NADH regeneration) under visible light with a higher yield% of about ~ 94.85%.

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Formation of reduced nicotinamide adenine dinucleotide peroxide.

Cited by 42 publications

References 28 publications

NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase

NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase

Class-II dihydroorotate dehydrogenases from three phylogenetically distant fungi support anaerobic pyrimidine biosynthesis

Highly Efficient S‐g‐CN/Mo‐368 Catalyst for Synergistically NADH Regeneration Under Solar Light

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