- CYTOKININS IN IMMATURE SEEDS OF DOLICHOS LABLAB
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Key Word Index - Dolichos lablab; Leguminoasae; cytokins; trans-zeatin; ribosyl-trans-zeatin; ribosyl-cis-zeatin; glucosyl-trans-zeatin; glucosyl ribosyl-trans-zeatin. Five cytokinins, trans-zeatin, 9-β-D-ribofuranosyl-trans-zeatin, 9-β-D-ribofuranosyl-cis-zeatin, 6-(trans-4-O-β-D-glucopyranosyl-3-methyl-2-butenylamino)purine and 6-(trans-4-O-β-D-glucopyranosyl-3-methyl-2-butenylamino)-9-β-D-ribofuranosylpurine were identified from immature seeds of Dolichos lablab.
- Yokota, Takao,Ueda, Junichi,Takahasi, Nobutaka
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- Chemoenzymatic synthesis of cytokinins from nucleosides: Ribose as a blocking group
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Nucleoside phosphorylases are involved in the salvage pathways of nucleoside biosynthesis and catalyze the reversible reaction of a nucleobase with α-d-ribose-1-phosphate to yield a corresponding nucleoside and an inorganic phosphate. The equilibrium of these reactions is shifted towards nucleosides, especially in the case of purines. Purine nucleoside phosphorylase (PNP, EC 2.4.2.1) is widely used in labs and industry for the synthesis of nucleosides of practical importance. Bacterial PNPs have relatively broad substrate specificity utilizing a wide range of purines with different substituents to form the corresponding nucleosides. To shift the reaction in the opposite direction we have used arsenolysis instead of phosphorolysis. This reaction is irreversible due to the hydrolysis of the resulting α-d-ribose-1-arsenate. As a result, heterocyclic bases are formed in quantitative yields and can be easily isolated. We have developed a novel method for the preparation of cytokinins based on the enzymatic cleavage of the N-glycosidic bond of N6-substituted adenosines in the presence of PNP and Na2HAsO4. According to the HPLC analysis the conversion proceeds in quantitative yields. In the proposed strategy the ribose residue acts as a protective group. No contamination of the final products with AsO43- has been detected via HPLC-HRMS; simple analytical arsenate detection via ESI-MS has been proposed.
- Oslovsky, Vladimir E.,Solyev, Pavel N.,Polyakov, Konstantin M.,Alexeev, Cyril S.,Mikhailov, Sergey N.
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p. 2156 - 2163
(2018/03/26)
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- Method for synthesizing adenine and derivatives thereof
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The invention discloses a method for synthesizing adenine and derivatives thereof. The method comprises the steps: firstly, subjecting diethyl malonate and dimethyl dioxirane to an oxidation reaction, so as to obtain 2-hydroxyldiethyl malonate; then, carrying out an ammonolysis reaction with ammonia water, so as to obtain 2-hydroxyl malonamide; then, carrying out a cyclization reaction with trimethyl orthoformate, so as to obtain 5-hydroxyl pyrimid-4,6-(1H,5H)-dione; then, carrying out a chlorination reaction with phosgene, so as to obtain 4,5,6-trichloropyrimidine; then, carrying out a cyclization reaction with formamidine hydrochloride, so as to obtain 4-chloro-1H-pyrazol[3, 4-d]pyrimidine; finally, carrying out an ammoniation reaction with ammonia water or an amine compound in the presence of triethylamine, thereby obtaining the adenine and derivatives thereof. According to the method, the raw materials are moderately-priced and readily available, the reaction conditions are mild, the reaction process is safe, the requirements on production equipment are low, particularly, the environmental pollution is light, and the yield is relatively high, so that the method is applicable to industrial large-scale production.
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Paragraph 0051; 0052
(2017/07/19)
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- Chemical modification of the plant isoprenoid cytokinin N 6-isopentenyladenosine yields a selective inhibitor of human enterovirus 71 replication
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In this study, we demonstrate that N6-isopentenyladenosine, which essentially is a plant cytokinin-like compound, exerts a potent and selective antiviral effect on the replication of human enterovirus 71 with an EC50 of 1.0 ± 0.2 ?1/4M and a selectivity index (SI) of 5.7. The synthesis of analogs with modification of the N6-position did not result in a lower EC50 value. However, in particular with the synthesis of N6-(5-hexene-2-yne-1-yl)adenosine (EC50 Combining double low line 4.3 ± 1.5 ?1/4M), the selectivity index was significantly increased: because of a reduction in the adverse effect of this compound on the host cells, an SI > 101 could be calculated. With this study, we for the first time provide proof that a compound class that is based on the plant cytokinin skeleton offers an interesting starting point for the development of novel antivirals against mammalian viruses, in the present context in particular against enterovirus 71.
- Tararov, Vitali I.,Tijsma, Aloys,Kolyachkina, Svetlana V.,Oslovsky, Vladimir E.,Neyts, Johan,Drenichev, Mikhail S.,Leyssen, Pieter,Mikhailov, Sergey N.
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p. 406 - 413
(2015/02/19)
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- Chemical modification of the plant isoprenoid cytokinin N6-isopentenyladenosine yields a selective inhibitor of human enterovirus 71 replication
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In this study, we demonstrate that N6-isopentenyladenosine, which essentially is a plant cytokinin-like compound, exerts a potent and selective antiviral effect on the replication of human enterovirus 71 with an EC50 of 1.0 ± 0.2 mM and a selectivity index (SI) of 5.7. The synthesis of analogs with modification of the N6-position did not result in a lower EC50 value. However, in particular with the synthesis of N6-(5-hexene-2-yne-1-yl)adenosine (EC50 = 4.3 ± 1.5 mM), the selectivity index was significantly increased: because of a reduction in the adverse effect of this compound on the host cells, an SI 101 could be calculated. With this study, we for the first time provide proof that a compound class that is based on the plant cytokinin skeleton offers an interesting starting point for the development of novel antivirals against mammalian viruses, in the present context in particular against enterovirus 71.
- Tararov, Vitali I.,Tijsma, Aloys,Kolyachkina, Svetlana V.,Oslovsky, Vladimir E.,Neyts, Johan,Drenichev, Mikhail S.,Leyssen, Pieter,Mikhailov, Sergey N.
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p. 406 - 413
(2015/05/04)
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- A purine nucleoside phosphorylase in Solanum tuberosum L. (potato) with specificity for cytokinins contributes to the duration of tuber endodormancy
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StCKP1 (Solanum tuberosum cytokinin riboside phosphorylase) catalyses the interconversion of the N9-riboside form of the plant hormone CK (cytokinin), a subset of purines, with its most active free base form. StCKP1 prefers CK to unsubstituted aminopurines. The protein was discovered as a CK-binding activity in extracts of tuberizing potato stolon tips, from which it was isolated by affinity chromatography. The N-terminal amino acid sequence matched the translation product of a set of ESTs, enabling a complete mRNA sequence to be obtained by RACE-PCR. The predicted polypeptide includes a cleavable signal peptide and motifs for purine nucleoside phosphorylase activity. The expressed protein was assayed for purine nucleoside phosphorylase activity against CKs and adenine/adenosine. Isopentenyladenine, trans-zeatin, dihydrozeatin and adenine were converted into ribosides in the presence of ribose 1-phosphate. In the opposite direction, isopentenyladenosine, trans-zeatin riboside, dihydrozeatin riboside and adenosine were converted into their free bases in the presence of Pi. StCKP1 had no detectable ribohydrolase activity. Evidence is presented that StCKP1 is active in tubers as a negative regulator of CKs, prolonging endodormancy by a chill-reversible mechanism.
- Bromley, Jennifer R.,Warnes, Barbara J.,Newell, Christine A.,Thomson, Jamie C.P.,James, Celia M.,Turnbull, Colin G.N.,Hanke, David E.
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p. 225 - 237
(2014/03/21)
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- Peroxide-shunt substrate-specificity for the Salmonella typhimurium O 2-dependent tRNA modifying monooxygenase (MiaE)
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Post-transcriptional modifications of tRNA are made to structurally diversify tRNA. These modifications alter noncovalent interactions within the ribosomal machinery, resulting in phenotypic changes related to cell metabolism, growth, and virulence. MiaE is a carboxylate bridged, nonheme diiron monooxygenase, which catalyzes the O2-dependent hydroxylation of a hypermodified-tRNA nucleoside at position 37 (2-methylthio-N6- isopentenyl-adenosine(37)-tRNA) [designated ms2i6A 37]. In this work, recombinant MiaE was cloned from Salmonella typhimurium, purified to homogeneity, and characterized by UV-visible and dual-mode X-band EPR spectroscopy for comparison to other nonheme diiron enzymes. Additionally, three nucleoside substrate-surrogates (i6A, Cl2i6A, and ms2i6A) and their corresponding hydroxylated products (io6A, Cl2io 6A, and ms2io6A) were synthesized to investigate the chemo- and stereospecificity of this enzyme. In the absence of the native electron transport chain, the peroxide-shunt was utilized to monitor the rate of substrate hydroxylation. Remarkably, regardless of the substrate (i6A, Cl2i6A, and ms2i6A) used in peroxide-shunt assays, hydroxylation of the terminal isopentenyl-C4-position was observed with >97% E-stereoselectivity. No other nonspecific hydroxylation products were observed in enzymatic assays. Steady-state kinetic experiments also demonstrate that the initial rate of MiaE hydroxylation is highly influenced by the substituent at the C2-position of the nucleoside base (v0/[E] for ms2i6A > i 6A > Cl2i6A). Indeed, the >3-fold rate enhancement exhibited by MiaE for the hydroxylation of the free ms 2i6A nucleoside relative to i6A is consistent with previous whole cell assays reporting the ms2io6A and io6A product distribution within native tRNA-substrates. This observation suggests that the nucleoside C2-substituent is a key point of interaction regulating MiaE substrate specificity.
- Corder, Andra L.,Subedi, Bishnu P.,Zhang, Siai,Dark, Amanda M.,Foss Jr., Frank W.,Pierce, Brad S.
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p. 6182 - 6196
(2013/10/01)
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- N9-Substituted N6-[(3-methylbut-2-en-1-yl)amino]purine derivatives and their biological activity in selected cytokinin bioassays
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Rational design is one of the latest ways how to evaluate particular activity of signal molecules, for example cytokinin derivatives. A series of N6-[(3-methylbut-2-en-1-yl)amino]purine (iP) derivatives specifically substituted at the N9 atom of purine moiety by tetrahydropyran-2-yl, ethoxyethyl, and C2-C4 alkyl chains terminated by various functional groups were prepared. The reason for this rational design was to reveal the relationship between specific substitution at the N9 atom of purine moiety of iP and cytokinin activity of the prepared compounds. The synthesis was carried out either via 6-chloro-9-substituted intermediates prepared originally from 6-chloropurine, or by a direct alkylation of N9 atom of N6-[(3- methylbut-2-en-1-yl)amino]purine. Selective reduction was implemented in the preparation of compound N6-[(3-methylbut-2-en-1-yl)amino]-9-(2- aminoethyl-amino)purine (12) when 6-[(3-methylbut-2-en-1-yl)amino]-9-(2- azidoethyl)purine (7) was reduced by zinc powder in mild conditions. The prepared derivatives were characterized by C, H, N elemental analyses, thin layer chromatography (TLC), high performance liquid chromatography (HPLC), melting point determinations (mp), CI+ mass spectral measurement (CI+ MS), and by 1H NMR spectroscopy. Biological activity of prepared compounds was assessed in three in vitro cytokinin bioassays (tobacco callus, wheat leaf senescence, and Amaranthus bioassay). Moreover, the perception of prepared derivatives by cytokinin-sensitive receptor CRE1/AHK4 from Arabidopsis thaliana, as well as by the receptors ZmHK1 and ZmHK3a from Zea mays, was studied in a bacterial assay where the response to the cytokinin treatment could be specifically quantified with the aim to reveal the way of the perception of the above mentioned derivatives in two different plant species, that is, Arabidopsis, a model dicot, and maize, a model monocot. The majority of cytokinin derivatives were significantly active in both Amaranthus as well as in tobacco callus bioassay and almost inactive in detached wheat leaf senescence assay. N9-Substituted iP derivatives remained active in both in vitro bioassays in a broad range of concentrations despite the fact that most of the derivatives were unable to trigger the cytokinin response in CRE1/AHK4 and ZmHK1 receptors. However, several derivatives induced low but detectable cytokinin-like activation in maize ZmHK3a receptor. Compound 6-[(3-methylbut-2-en-1-yl)amino]- 9-(tetrahydropyran-2-yl)purine (1) was also recognized by CRE1/AHK4 at high concentration ≥50 μM.
- Mik, Václav,Szü?ová, Lucie,Spíchal, Luká?,Plíhal, Ond?ej,Nisler, Jaroslav,Zahajská, Lenka,Dole?al, Karel,Strnad, Miroslav
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p. 7244 - 7251
(2012/01/19)
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- N6-acetyl-2,3,5-tri-O-acetyladenosine; A convenient, missed out substrate for regioselective N6-alkylations
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A simple and efficient route to N6-acetyl-2,3,5-tri-O- acetyladenosine (1) was developed based on selective N-deacetylation of pentaacetylated adenosine 2 with methanol at room temperature in the presence of imidazole. Preparative synthesis of 1 was elaborated utilizing a crude mixture of 2 and 1 which is produced by reaction of adenosine with acetic anhydride in pyridine at elevated temperatures. The total yield of 1 was 80-85% starting with adenosine. It was shown that 1 is a convenient substrate for selective N 6-alkylations. The study revealed the same regioselectivity in base-promoted reactions of 1 with activated alkyl halides and Mitsunobu reactions of 1 with alcohols. A series of N6-alkyladenosines 5a-f were prepared. Cytokinins 6b,d,e were prepared by enzymatic transformation of parent nucleoside derivatives 5b,d,e using a combination of nucleoside phosphorylase and alkaline phosphatase. Georg Thieme Verlag Stuttgart, New York.
- Tararov, Vitali I.,Kolyachkina, Svetlana V.,Alexeev, Cyril S.,Mikhailov, Sergey N.
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p. 2483 - 2489
(2011/09/20)
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- Thermal characterization of the solid state and raw material fluconazole by thermal analysis and pyrolysis coupled to GC/MS
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This article had studied the thermal characterization of the raw material and different fluconazole crystals, obtained through recrystallization with different solvents using thermoanalytical techniques (TG, DTA, DSC-50, DSC Photovisual, DSC-60) and Pyr-GC/MS. The results confirmed that the fluconazole volatilizes without decomposition until 250 °C. Pyr-GC/MS showed hexachlorobenzene like impurities in fluconazole raw material.
- Moura, Elisana Afonso,Correia, Lidiane Pinto,Pinto, Marcia Ferraz,Procopio, Jose Valdilanio Virgulino,De Souza, Fabio Santos,MacEdo, Rui Oliveira
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p. 289 - 293
(2010/08/04)
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