68-94-0Relevant articles and documents
The inhibitory effect of citrus flavonoids naringenin and hesperetin against purine nucleoside phosphorylase: Spectroscopic, atomic force microscopy and molecular modeling studies
Gong, Deming,Lv, Xingang,Ren, Er-Fang,Wang, Lang-Hong,Wang, Qilei
, (2020)
In this work, the inhibitory effect of two citrus flavonoids naringenin and hesperetin on human purine nucleoside phosphorylase (hPNP) and their binding mechanism were evaluated. Results from enzymatic kinetics revealed that naringenin and hesperetin reversibly inhibited hPNP via a mixed-type manner with IC50 values of 4.83 × 10?4 M and 5.32 × 10?4 M, respectively. Analysis of molecular modeling revealed that both naringenin and hesperetin bound directly into the active site by generating multiple forces including hydrogen bonding, π–π and π-Alkyl interactions with His64, Glu201, Ser220, His257, Phe200 and Val217 residues of hPNP, which caused the inhibition of hPNP activity. Moreover, conformational analysis by three-dimension fluorescence, circular dichroism and atomic force microscopy revealed that the binding of naringenin and hesperetin to hPNP induced changes in the microenvironment, secondary structure and morphology of hPNP. These results suggested that occupying the active site and enzymatic conformational perturbation induced by naringenin and hesperetin are the main reasons for reducing the inhibition of hPNP activity, which would be helpful in understanding the inhibitory mechanism of naringenin and hesperetin against hPNP.
Calcium-stimulated guanosine-inosine nucleosidase from yellow lupin (Lupinus luteus)
Szuwart, Maciej,Starzynska, Elzbieta,Pietrowska-Borek, Malgorzata,Guranowski, Andrzej
, p. 1476 - 1485 (2006)
Guanosine-inosine-preferring nucleoside N-ribohydrolase has been purified to homogeneity from yellow lupin (Lupinus luteus) seeds by ammonium sulfate fractionation, ion-exchange chromatography and gel filtration. The enzyme functions as a monomeric, 80 kDa polypeptide, most effectively between pH 4.7 and 5.5. Of various mono- and divalent cations tested, Ca2+ appeared to stimulate enzyme activity. The nucleosidase was activated 6-fold by 2 mM exogenous CaCl2 or Ca(NO3)2, with Ka = 0.5 mM (estimated for CaCl2). The Km values estimated for guanosine and inosine were 2.7 ± 0.3 μM. Guanosine was hydrolyzed 12% faster than inosine while adenosine and xanthosine were poor substrates. 2′-Deoxyguanosine, 2′-deoxyinosine, 2′-methylguanosine, pyrimidine nucleosides and 5′-GMP were not hydrolyzed. However, the enzyme efficiently liberated the corresponding bases from synthetic nucleosides, such as 1-methylguanosine, 7-methylguanosine, 1-N2-ethenoguanosine and 1-N2-isopropenoguanosine, but hydrolyzed poorly the ribosides of 6-methylaminopurine and 2,6-diaminopurine. MnCl2 or ZnCl2 inhibited the hydrolysis of guanosine with I50 ≈ 60 μM. Whereas 2′-deoxyguanosine, 2′-methylguanosine, adenosine, as well as guanine were competitive inhibitors of this reaction (Ki values were 1.5, 3.6, 21 and 9.7 μM, respectively), hypoxanthine was a weaker inhibitor (Ki = 64 μM). Adenine, ribose, 2-deoxyribose, 5′-GMP and pyrimidine nucleosides did not inhibit the enzyme. The guanosine-inosine hydrolase activity occurred in all parts of lupin seedlings and in cotyledons it increased up to 5-fold during seed germination, reaching maximum in the third/fourth day. The lupin nucleosidase has been compared with other nucleosidases.
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Taylor,Cheng
, p. 9. (1959)
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Assay of purine nucleoside phosphorylase in erythrocytes by flow-injection analysis with fluorescence detection
Hayashi,Zaitsu,Ohkura
, p. 4574 - 4578 (1987)
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Phloroglucinols Inhibit Chemical Mediators and Xanthine Oxidase, and Protect Cisplatin-Induced Cell Death by Reducing Reactive Oxygen Species in Normal Human Urothelial and Bladder Cancer Cells
Lin, Kai-Wei,Huang, A.-Mei,Tu, Huang-Yao,Weng, Jing-R.U.,Hour, Tzyh-Chyuan,Wei, Bai-Luh,Yang, Shyh-Chyun,Wang, Jih-Pyang,Pu, Yeong-Shiau,Lin, Chun-Nan
, p. 8782 - 8787 (2009)
Phloroglucinols, garcinielliptones HA-HE (1-5), and C (6) were studied in vitro for their inhibitory effects on chemical mediators released from mast cells, neutrophils, and macrophages. Compound 6 revealed significant inhibitory effect on release of lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB). Compounds 3, 4, and 6 showed significant inhibitory effects on superoxide anion generation in rat neutrophils stimulated with (fMLP)/(CB), while compounds 1 and 5 revealed inhibitory effects on tumor necrosis factor-α (TNF-α) formation in macrophages stimulated with lipopolysaccharide (LPS). Compounds 1 and 3-6 showed inhibitory effects on xanthine oxidase (XO) and could inhibit the DNA breakage caused by O2-.. Treatment of NTUB1 with 2 to 60 μM compound 3 and 5 μM cisplatin and SV-HUC1 with 9 to 60 μM 3 and 5 μM cisplatin, respectively, resulted in an increase of viability of cells. These results indicated that compounds 1 and 3-6 showed anti-inflammatory effects and antioxidant activities. Compound 3 mediates through the suppression of XO activity and reduction of reactive oxygen species (ROS), and protection of subsequent cell death.
Thermodynamic Reaction Control of Nucleoside Phosphorolysis
Kaspar, Felix,Giessmann, Robert T.,Neubauer, Peter,Wagner, Anke,Gimpel, Matthias
supporting information, p. 867 - 876 (2020/01/24)
Nucleoside analogs represent a class of important drugs for cancer and antiviral treatments. Nucleoside phosphorylases (NPases) catalyze the phosphorolysis of nucleosides and are widely employed for the synthesis of pentose-1-phosphates and nucleoside analogs, which are difficult to access via conventional synthetic methods. However, for the vast majority of nucleosides, it has been observed that either no or incomplete conversion of the starting materials is achieved in NPase-catalyzed reactions. For some substrates, it has been shown that these reactions are reversible equilibrium reactions that adhere to the law of mass action. In this contribution, we broadly demonstrate that nucleoside phosphorolysis is a thermodynamically controlled endothermic reaction that proceeds to a reaction equilibrium dictated by the substrate-specific equilibrium constant of phosphorolysis, irrespective of the type or amount of NPase used, as shown by several examples. Furthermore, we explored the temperature-dependency of nucleoside phosphorolysis equilibrium states and provide the apparent transformed reaction enthalpy and apparent transformed reaction entropy for 24 nucleosides, confirming that these conversions are thermodynamically controlled endothermic reactions. This data allows calculation of the Gibbs free energy and, consequently, the equilibrium constant of phosphorolysis at any given reaction temperature. Overall, our investigations revealed that pyrimidine nucleosides are generally more susceptible to phosphorolysis than purine nucleosides. The data disclosed in this work allow the accurate prediction of phosphorolysis or transglycosylation yields for a range of pyrimidine and purine nucleosides and thus serve to empower further research in the field of nucleoside biocatalysis. (Figure presented.).
Structural and biochemical characterization of the nucleoside hydrolase from C. elegans reveals the role of two active site cysteine residues in catalysis
Singh, Ranjan Kumar,Steyaert, Jan,Versées, Wim
, p. 985 - 996 (2017/05/01)
Nucleoside hydrolases (NHs) catalyze the hydrolysis of the N-glycoside bond in ribonucleosides and are found in all three domains of life. Although in parasitic protozoa a role in purine salvage has been well established, their precise function in bacteria and higher eukaryotes is still largely unknown. NHs have been classified into three homology groups based on the conservation of active site residues. While many structures are available of representatives of group I and II, structural information for group III NHs is lacking. Here, we report the first crystal structure of a purine-specific nucleoside hydrolase belonging to homology group III from the nematode Caenorhabditis elegans (CeNH) to 1.65? resolution. In contrast to dimeric purine-specific NHs from group II, CeNH is a homotetramer. A cysteine residue that characterizes group III NHs (Cys253) structurally aligns with the catalytic histidine and tryptophan residues of group I and group II enzymes, respectively. Moreover, a second cysteine (Cys42) points into the active site of CeNH. Substrate docking shows that both cysteine residues are appropriately positioned to interact with the purine ring. Site-directed mutagenesis and kinetic analysis proposes a catalytic role for both cysteines residues, with Cys253 playing the most prominent role in leaving group activation.