134434-48-3Relevant academic research and scientific papers
Monitoring hydrothermal reactions on the millisecond time scale using a micro-tube flow reactor and kinetics of ATP hydrolysis for the RNA world hypothesis
Kawamura
, p. 1805 - 1811 (2000)
A new method for monitoring hydrothermal reactions on the millisecond time scale has been developed using a microtube flow reactor. The system was designed based on a high-pressure pump, a sample-loop injector, a narrow-bore size capillary, a cooling bath, back-pressure tubing, and a sampling port. Samples were analyzed using high-performance liquid chromatography. Kinetic analyses of the hydrolyses of adenosine 5'-triphosphate (ATP) and adenosine 5'-monophosphate (AMP) on the millisecond time range at 250 - 315 °C were demonstrated so as to evaluate the performance of the method. In conclusion, monitoring was successful for the hydrolysis of ATP and AMP in 2 - 50 ms using fused-silica capillary tubing with 0.015 and 0.025 mm inner diameter (ID). The method enables real-time monitoring of hydrothermal reactions in about 100-times shorter time range than other techniques. This paper proposes apparent rate constants and activation energy for the consecutive hydrolysis of ATP to adenine at high temperatures that were difficult to determine by a conventional batch method. On the basis of the rate constants, kinetics and mechanistic analyses of the step-wise decomposition of ATP were investigated from the viewpoint of the RNA world hypothesis under hydrothermal environments.
CYTOKININ CATABOLISM AND CYTOKININ OXIDASE
McGaw, Brian A.,Horgan, Roger
, p. 1103 - 1106 (1983)
Cytokinin oxidase has been highly purified from mature Zea mays kernels.Adenine has been unambiguously identified, by HPLC co-chromatography, UV and mass spectroscopy, to be the oxidation product of N6-(Δ2-isopentenyl)adenine by this enzyme.No other products were detected.The results are in agreement with metabolic studies and suggest that cytokinin oxidase plays an important role in the catabolism of exogenously applied cytokinins. - Key Word Index: Zea mays; Gramineae; kernels; cytokinin oxidase; N6-(Δ2-isopentenyl) adenine; adenine; HPLC.
Monitoring of hydrothermal reactions in 3 ms using fused-silica capillary tubing
Kawamura, Kunio
, p. 125 - 126 (1999)
Monitoring of hydrothermal reactions in the time range of 3-1000 ms was succeeded by flow reactor using fused-silica capillary tubing. The technique was applied for measuring the hydrolysis rate of ATP at 250 °C in which the minimum monitoring time was 3.1 ms. The rate constants of ATP hydrolysis was consistent with that was extrapolated of the Arrhenius plots in our previous study. This method enables milli-second monitoring of hydrothermal reactions.
Hydrolytic reactions of diadenosine 5′,5′-triphosphate
Mikkola, Satu
, p. 770 - 776 (2004)
The hydrolysis of diadenosine 5′,5′-triphosphate to AMP and ADP has been studied over a wide pH-range. Under acidic conditions the reaction shows a first-order dependence on the hydronium ion concentration. Below pH 3 the rate-increase begins to level off. From pH 6 to 9 the hydrolysis is slow and pH-independent. Base-catalysed hydrolysis is observed in NaOH-solutions. Under alkaline conditions an intramolecular nucleophilic attack on the phosphate producing 3′,5′-cAMP is also observed, but it is slower than the intermolecular reaction. Depurination of the adenosine moieties competes with the hydrolysis both under acidic and alkaline conditions, but the mechanisms are different. The temperature-dependence of the hydrolysis of Ap3A and the depurination of adenosine moieties were studied under acidic conditions, and the activation parameters of the reactions were calculated. The results of the work reflect the fact that the negatively charged polyphosphate group is very resistant towards nucleophilic attack. An efficient catalysis is only observed under acidic conditions, where the phosphate group becomes protonated. General acids or bases did not catalyse the hydrolysis. Furthermore, hydroxide ion catalysed cleavage is only observed at high base concentrations and other negatively charged nucleophiles did not attack the phosphate groups of diadenosine polyphosphates.
Continuous fluorescence assays for reactions involving adenine
Firestone, Ross,Cameron, Scott,Tyler, Peter,Ducati, Rodrigo,Spitz, Adam,Schramm, Vern
, p. 11860 - 11867 (2016)
5′-Methylthioadenosine phosphorylase (MTAP) and 5′-methylthioadenosine nucleosidase (MTAN) catalyze the phosphorolysis and hydrolysis of 5′-methylthioadenosine (MTA), respectively. Both enzymes have low KM values for their substrates. Kinetic assays for these enzymes are challenging, as the ultraviolet absorbance spectra for reactant MTA and product adenine are similar. We report a new assay using 2-amino-5′-methylthioadenosine (2AMTA) as an alternative substrate for MTAP and MTAN enzymes. Hydrolysis or phosphorolysis of 2AMTA forms 2,6-diaminopurine, a fluorescent and easily quantitated product. We kinetically characterize 2AMTA with human MTAP, bacterial MTANs and use 2,6-diaminopurine as a fluorescent substrate for yeast adenine phosphoribosyltransferase. 2AMTA was used as the substrate to kinetically characterize the dissociation constants for three-transition-state analogue inhibitors of MTAP and MTAN. Kinetic values obtained from continuous fluorescent assays with MTA were in good agreement with previously measured literature values, but gave smaller experimental errors. Chemical synthesis from ribose and 2,6-dichloropurine provided crystalline 2AMTA as the oxalate salt. Chemo-enzymatic synthesis from ribose and 2,6-diaminopurine produced 2-amino-S-adenosylmethionine for hydrolytic conversion to 2AMTA. Interaction of 2AMTA with human MTAP was also characterized by pre-steady-state kinetics and by analysis of the crystal structure in a complex with sulfate as a catalytically inert analogue of phosphate. This assay is suitable for inhibitor screening by detection of fluorescent product, for quantitative analysis of hits by rapid and accurate measurement of inhibition constants in continuous assays, and pre-steady-state kinetic analysis of the target enzymes.
Interaction between isoamyl adenine and rice cytokinin oxidase
Fang, Yujiao,Li, Yong,Liang, Xiaosheng,Xiao, Qian,Wu, Yunhua
, p. 362 - 366 (2016)
Cytokinin (CTK) dehydrogenase is responsible for regulating the endogenous CTK content by oxidative removal of the side chain. Herein, we have applied fluorescence method to study the interaction between CTK dehydrogenase and CTK in vitro and obtain some parameters of their interaction. We found that addition of isopentenyl adenine can quench the fluorescence of CTK dehydrogenase, and the quenching mechanism was to be a static quenching procedure. We have measured the number of binding sites n and the apparent binding constant K and have calculated the thermodynamics parameter ΔH, ΔG, and ΔS by fluorescence quenching method. Based on thermodynamics parameter’s results, we concluded that their binding reaction was both entropy driven and the enthalpy driven, and the Van der Waals force and hydrogen bond force played a major role in the interaction. Based on the synchronous fluorescence spectrometry results, we demonstrated that the binding site between isopentenyl adenine and CTK dehydrogenase is in the microenvironment of both tryptophan and tyrosine. The fluorescence signal of coenzyme, flavin adenine dinucleotide, decreases gradually with the addition of isopentenyl adenine. And this method can be used for isopentenyl adenine routine assay. Under optimized experimental parameters, the linear segment increases from 0.6?μM to 100?μM with a regression equation of ΔF?=?0.04?+?0.15cip (r?=?0.999, cip in μM) with the detection limit of 0.15?μM iP.
Characterization of inosine-uridine nucleoside hydrolase (RihC) from Escherichia coli
Arivett, Brock,Farone, Mary,Masiragani, Ranjith,Burden, Andrew,Judge, Shelby,Osinloye, Adedoyin,Minici, Claudia,Degano, Massimo,Robinson, Matthew,Kline, Paul
, p. 656 - 662 (2014)
A non-specific nucleoside hydrolase from Escherichia coli (RihC) has been cloned, overexpressed, and purified to greater than 95% homogeneity. Size exclusion chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis show that the protein exists as a homodimer. The enzyme showed significant activity against the standard ribonucleosides with uridine, xanthosine, and inosine having the greatest activity. The Michaelis constants were relatively constant for uridine, cytidine, inosine, adenosine, xanthosine, and ribothymidine at approximately 480 μM. No activity was exhibited against 2′-OH and 3′-OH deoxynucleosides. Nucleosides in which additional groups have been added to the exocyclic N6 amino group also exhibited no activity. Nucleosides lacking the 5′-OH group or with the 2′-OH group in the arabino configuration exhibited greatly reduced activity. Purine nucleosides and pyrimidine nucleosides in which the N7 or N3 nitrogens respectively were replaced with carbon also had no activity.
Studies on disaccharide nucleoside synthesis. Mechanism of the formation of trisaccharide purine nucleosides
Mikhailov, Sergey N.,Rodionov, Andrei A.,Efimtseva, Ekaterina V.,Ermolinsky, Boris S.,Fomitcheva, Marina V.,Padyukova, Nelly Sh.,Rothenbacher, Klaus,Lescrinier, Eveline,Herdewijn, Piet
, p. 691 - 692 (1999)
The unexpected formation of trisaccharide nucleosides during synthesis of purine 5'-O-β-D-ribofuranosylnucleosides in the presence of Lewis acids was observed.
Meteorite-catalyzed intermoleculartrans-glycosylation produces nucleosides under proton beam irradiation
Bizzarri, Bruno Mattia,Fanelli, Angelica,Kapralov, Michail,Krasavin, Eugene,Saladino, Raffaele
, p. 19258 - 19264 (2021/06/03)
Di-glycosylated adenines act as glycosyl donors in the intermoleculartrans-glycosylation of pyrimidine nucleobases under proton beam irradiation conditions. Formamide and chondrite meteorite NWA 1465 increased the yield and the selectivity of the reaction
One-Step Synthesis of 2-Fluoroadenine Using Hydrogen Fluoride Pyridine in a Continuous Flow Operation
Salehi Marzijarani, Nastaran,Snead, David R.,McMullen, Jonathan P.,Lévesque, Fran?ois,Weisel, Mark,Varsolona, Richard J.,Lam, Yu-Hong,Liu, Zhijian,Naber, John R.
supporting information, p. 1522 - 1528 (2019/07/10)
We report the development of a one-pot synthesis of 2-fluoroadenine from an inexpensive 2,6-diaminopurine starting material using diazonium chemistry in a continuous fashion. Given the sensitivity of this transformation to temperature, we conducted critical experiments to study the exothermicity of the reaction and the heat removal, which were critical for the development of the process. Our goal was to improve the yield and purity of this pharmaceutical intermediate (2-fluoroadenine) and develop a more robust process.
