Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Heterocycles  

Mesothelioma is a severe tumor formed in pleura and peritoneum, for which no useful molecular-targeting therapy is available. We synthesized several derivatives of NMDI14, which is a reported inhibitor for non-sense mediated mRNA decay, and evaluated the activity of the NMDI14 derivatives as potential anti-mesothelioma agents. Some of the synthesized compounds showed promising activity in terms of cytotoxicity toward mesothelioma model cells and promotion of GAS5 expression selectively in mesothelioma cells. These results indicate that the NMDI14 derivatives may be useful for further developing clinically effective anti-mesothelioma drugs.

DOI： 10.3987/COM-19-14191

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Pharmaceutical Society of Japan  

<p>Efficient methods for delivery of antisense DNA or small interfering RNA (siRNA) are highly needed. Cationic materials, which are conventionally used for anionic oligonucleotide delivery, have several drawbacks, including aggregate formation, cytotoxicity and a low endosome escape efficiency. In this report a bio-reactive mask (<i>i.e.</i>, disulfide unit) for cationic amino groups was introduced, and the mask was designed such that it was removed at the target cell surface. Insolubility and severe cellular toxicity caused by exposed cationic groups are avoided when using the mask. Moreover, the disulfide unit used to mask the cationic group enabled direct delivery of oligonucleotides to the cell cytosol. The molecular design reported is a promising approach for therapeutic applications.</p>

DOI： 10.1248/cpb.c19-00811

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CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

Development of intracellular delivery methods for antisense DNA and siRNA is important. Previously reported methods using liposomes or receptor-ligands take several hours or more to deliver oligonucleotides to the cytoplasm due to their retention in endosomes. Oligonucleotides modified with low molecular weight disulfide units at a terminus reach the cytoplasm 10 minutes after administration to cultured cells. This rapid cytoplasmic internalization of disulfide-modified oligonucleotides suggests the existence of an uptake pathway other than endocytosis. Mechanistic analysis revealed that the modified oligonucleotides are efficiently internalized into the cytoplasm through disulfide exchange reactions with the thiol groups on the cellular surface. This approach solves several critical problems with the currently available methods for enhancing cellular uptake of oligonucleotides and may be an effective approach in the medicinal application of antisense DNA and siRNA.

DOI： 10.1002/anie.201900993

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Language：English   Publishing type：Research paper (scientific journal)  

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Controlling PCR fidelity is an important issue for molecular biology and high-fidelity PCR is essential for gene cloning. In general, fidelity control is achieved by protein engineering of polymerases. In contrast, only a few studies have reported controlling fidelity using chemically modified nucleotide substrates. In this report, we synthesized nucleotide substrates possessing a modification on Pγ and evaluated the effect of this modification on PCR fidelity. One of the substrates, nucleotide tetraphosphate, caused a modest decrease in Taq DNA polymerase activity and the effect on PCR fidelity was dependent on the type of mutation. The use of deoxyadenosine tetraphosphate enhanced the A:T→G:C mutation dramatically, which is common when using Taq polymerase. Conversely, deoxyguanosine tetraphosphate (dG4P) suppressed this mutation but increased the G:C→A:T mutation during PCR. Using an excess amount of dG4P suppressed both mutations successfully and total fidelity was improved.

DOI： 10.1002/cbic.202200572

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

We herein report a new synthetic method of nucleoside oligophosphates based on an electrophilic activation of 5'-phosphorothioate nucleotides. Treatment of the phosphorothioate with 2,4-dinitrochlorobenzene (DNCB) efficiently afforded the key activated...

DOI： 10.1039/d2ob02260e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.bmcl.2022.128939

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Removing immunogenic uncapped mRNA from in vitro transcribed mRNA is critical in mRNA research and clinical applications. Commonly used capping methods provide a maximum capping efficiency of around 80-90% for widely used Cap-0- and Cap-1-type mRNAs. However, uncapped and capped mRNA possesses almost identical physicochemical properties, posing challenges to their physical separation. Herein, we developed hydrophobic photocaged tag-modified cap analogs, which separated capped mRNA from uncapped mRNA by reversed-phase HPLC. Subsequent photo-irradiation recovers footprint-free native capped mRNA. This approach provided 100% capping efficiency even in Cap-2-type mRNA with versatility applicable to 650 nt and 4,247 nt mRNA. The Cap-2-type mRNA showed up to 3 to 4-fold higher translational activity in cultured cells and animals than mRNA prepared by the standard capping method. Notably, the purification process simultaneously removed immunogenic double-stranded mRNA, another major contaminant of in vitro transcribed mRNA, drastically reducing mRNA immunogenicity in cultured cells.

DOI： 10.26434/chemrxiv-2022-vfjt6

Language：English   Publishing type：Research paper (scientific journal)  

Synthetic phosphate-derived functional groups are important for controlling the function of bioactive molecules in vivo. Herein we describe the development of a new type of biocompatible phosphate analog, a fluorophosphoramidate (FPA) functional group that has characteristic P-F and P-N bonds. We found that FPA with a primary amino group was relatively unstable in aqueous solution and was converted to a monophosphate, while FPA with a secondary amino group was stable. Furthermore, by improving the molecular design of FPA, we developed a reaction in which a secondary amino group is converted to a primary amino group in the intracellular environment and clarified that the FPA group functions as a phosphate prodrug of nucleoside. Various FPA-gemcitabine derivatives were synthesized and their toxicity to cancer cells were evaluated. One of the FPA-gemcitabine derivatives showed superior toxicity compared with gemcitabine and its ProTide prodrug, which methodology is widely used in various nucleoside analogs, including anti-cancer and anti-virus drugs.

DOI： 10.1002/cmdc.202200188

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Language：English   Publishing type：Research paper (scientific journal)  

Site-specific chemical modification of mRNA can improve its translational efficiency and stability. For this purpose, it is desirable to develop a complete chemical synthesis method for chemically modified mRNA. The key is a chemical reaction that introduces a cap structure into the chemically synthesized RNA. In this study, we developed a fast and quantitative chemical capping reaction between 5'-phosphorylated RNA and N7-methylated GDP imidazolide in the presence of 1-methylimidazole in the organic solvent dimethyl sulfoxide. It enabled quantitative preparation of capping RNA within 3 h. We prepared chemically modified 107-nucleotide mRNAs, including N6-methyladenosine, insertion of non-nucleotide linkers, and 2'-O-methylated nucleotides at the 5' end and evaluated their effects on translational activity in cultured HeLa cells. The results showed that mRNAs with non-nucleotide linkers in the untranslated regions were sufficiently tolerant to translation and that mRNAs with the Cap_2 structure had higher translational activity than those with the Cap_0 structure.

DOI： 10.1021/acschembio.1c00996

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

We have found that antisense oligonucleotides and siRNA molecules modified with repeat structures of disulfide units can be directly introduced into the cytoplasm and exhibit a suppressive effect on gene expression. In this study, we analyzed the mechanism of cellular uptake of these membrane-permeable oligonucleotides (MPONs). Time-course analysis by confocal microscopy showed that the uptake of MPONs from the plasma membrane to the cytoplasm reached 50 % of the total uptake in about 5 min. In addition, analysis of the plasma membrane proteins to which MPONs bind, identified several proteins, including voltage-dependent anion channel. Next, we analyzed the behavior of MPONs in the cell and found them to be abundant in the nucleus as early as 24 h after addition with the amount increasing further after 48 and 72 h. The amount of MPONs was 2.5-fold higher than that of unmodified oligonucleotides in the nucleus after 72 h. We also designed antisense oligonucleotides and evaluated the effect of MPONs on mRNA exon skipping using DMD model cells; MPONs caused exon skipping with 69 % efficiency after 72 h, which was three times higher than the rate of the control. In summary, the high capacity for intracytoplasmic and nuclear translocation of MPONs is expected to be useful for therapeutic strategies targeting exon skipping.

DOI： 10.1002/cbic.202100413

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/cbic.202100312

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Acquired immunodeficiency syndrome (AIDS) is caused by infection with the human immunodeficiency virus (HIV). Although treatments against HIV infection are available, AIDS remains a serious disease that causes many deaths annually. Although a variety of anti-HIV drugs have been synthesized and marketed to treat HIV-infected patients, nucleoside analogue reverse transcriptase inhibitors (NRTIs), which mimic nucleosides, are used extensively and remain a subject of interest to medicinal chemists. However, HIV has acquired drug resistance against NRTIs, and thus the struggle to find novel therapies continues. In this review, we trace the trajectory of NRTIs, focusing on the synthesis, mechanisms of action and applications of NRTIs that have been developed.

DOI： 10.1002/cmdc.202000695

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/cmdc.202000695

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(公社)日本薬学会  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Messenger RNAs (mRNAs) with phosphorothioate modification (PS-mRNA) to the phosphate site of A, G, C, and U with all 16 possible combinations were prepared, and the translation reaction was evaluated using an E. coli cell-free translation system. Protein synthesis from PS-mRNA increased in 12 of 15 patterns when compared with that of unmodified mRNA. The protein yield increased 22-fold when the phosphorothioate modification at A/C sites was introduced into the region from the 5'-end to the initiation codon. Single-turnover analysis of PS-mRNA translation showed that phosphorothioate modification increases the number of translating ribosomes, thus suggesting that the rate of translation initiation (rate of ribosome complex formation) is positively affected by the modification. The method provides a new strategy for improving translation by using non-natural mRNA.

DOI： 10.1002/anie.202007111

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/anie.202007111

Language：Japanese   Publishing type：Research paper (scientific journal)  

Can current simulations quantitatively predict the stability of ribonucleic acids (RNAs)? In this research, we apply a free-energy perturbation simulation of RNAs containing inosine, a modified ribonucleic base, to the derivation of RNA nearest-neighbor parameters. A parameter set derived solely from 30 simulations was used to predict the free-energy difference of the RNA duplex with a mean unbiased error of 0.70 kcal/mol, which is a level of accuracy comparable to that obtained with parameters derived from 25 experiments. We further show that the error can be lowered to 0.60 kcal/mol by combining the simulation-derived free-energy differences with experimentally measured differences. This protocol can be used as a versatile method for deriving nearest-neighbor parameters of RNAs with various modified bases.

DOI： 10.1021/acs.jctc.0c00270

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>Circular RNA without a stop codon enables rolling circle translation. we carried out one-pot chemical synthesis of circular RNA from RNA fragments. The synthesized circular RNAs acted as translation templates, despite the presence of unnatural phosphoramidate linkages.</p>

DOI： 10.1039/d0cc02140g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

Eukaryotic mRNA has a cap structure at the 5' end and a poly(A) tail at the 3' end. The cap and poly(A) tail form a complex with multiple translation factors, and mRNA forms a circularized structure called a closed-loop model. This circularized structure reportedly not only stabilizes mRNA but also promotes ribosome recycling during translation, which improves translation efficiency. We designed an artificial mRNA that forms a circularized structure without a cap structure and poly(A) tail and found that its translational efficiency was improved compared with that of a sequence without the circularized structure in a eukaryotic translation system.

DOI： 10.1080/15257770.2019.1671593

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor & Francis  

MicroRNAs (miRNAs) are small non-coding RNAs that play essential roles in the regulation of gene function by a mechanism known as RNA silencing. In a previous study, we revealed that miRNA-mediated silencing efficacy is correlated with the combinatorial thermodynamic properties of the miRNA seed-target mRNA duplex and the 5´-terminus of the miRNA duplex, which can be predicted using 'miScore'. In this study, a robust refined-miScore was developed by integrating the thermodynamic properties of various miRNA secondary structures and the latest thermodynamic parameters of wobble base-pairing, including newly established parameters for I:C base pairing. Through repeated random sampling and machine learning, refined-miScore models calculated with either melting temperature (Tm) or free energy change (ΔG) values were successfully built and validated in both wild-type and adenosine-to-inosine edited miRNAs. In addition to the previously reported contribution of the seed-target duplex and 5´-terminus region, the refined-miScore suggests that the central and 3´-terminus regions of the miRNA duplex also play a role in the thermodynamic regulation of miRNA-mediated silencing efficacy.

DOI： 10.1080/15476286.2019.1678364

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

We herein report a new approach for RNA interference, so-called "build-up RNAi" approach, where single-strand circular RNAs with a photocleavable unit or disulfide moiety were used as siRNA precursors. The advantages of using these circular RNA formats for RNAi were presented in aspects of immunogenicity and cellular uptake.

DOI： 10.1039/c9cc04872c

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Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor & Francis  

PMID: 31298608

DOI： 10.1080/15257770.2019.1641205

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.201900993

Language：English   Publishing type：Research paper (scientific journal)  

Glutathione S-transferase π (GSTP1-1 ) is overexpressed in many types of cancer and is involved in drug resistance. Therefore, GSTP1-1 is an important target in cancer therapy, and many GST inhibitors have been reported. We had previously developed an irreversible inhibitor, GS-ESF, as an effective GST inhibitor; however, its cellular permeability was too low for it to be used in inhibiting intracellular GST. We have now developed new irreversible inhibitors by introducing sulfonyl fluoride (SF) into chloronitrobenzene (CNB). The mechanism of action was revealed to be that CNBSF first reacts with glutathione (GSH) through an aromatic substitution in the cell, then the sulfonyl group on the GSH conjugate with CNBSF reacts with Tyr108 of GST to form a sulfonyl ester bond. Our new inhibitor irreversible inhibited GSTP1-1 both in vitro and in cellulo with a long duration of action.

DOI： 10.1002/cbic.201800671

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Other Link： http://orcid.org/0000-0002-3609-602X

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(公社)日本薬学会  

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(公社)日本薬学会  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cold Spring Harbor Laboratory  

<title>Abstract</title>In RNA secondary structure prediction, nearest-neighbor parameters are used to determine the stability of a given structure. We derived the nearest-neighbor parameters for RNAs containing inosine-cytosine pairs. For parameter derivation, we developed a method that combines UV adsorption measurement experiments with free-energy calculations using molecular dynamics simulations. The method provides fast drop-in parameters for modified bases. Derived parameters were compared and found to be consistent with existing parameters for canonical RNAs. A duplex with an internal inosine-cytosine pair is 0.9 kcal/mol more unstable than the same duplex with an internal guanine-cytosine pair, and is as stable as the one with an internal adenine-uracil pair (only 0.1 kcal/mol more stable) on average.

DOI： 10.1101/454124

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Pharmaceutical Society of Japan  

Chemical ligation of oligonucleotides (ONs) is the key reaction for various ON-based technologies. We have tried to solve the problems of RNA interference (RNAi) technology by applying ON chemical ligation to RNAi. We designed a new RNAi system, called intracellular buildup RNAi (IBR-RNAi), where the RNA fragments are built up into active small-interference RNA (siRNA) in cells through a chemical ligation reaction. Using the phosphorothioate and iodoacetyl groups as reactive functional groups for the ligation, we achieved RNAi effects without inducing immune responses. Additionally, we developed a new chemical ligation for IBR-RNAi, which affords a more native-like structure in the ligated product. The new ligation method should be useful not only for IBR-RNAi but also for the chemical synthesis of biofunctional ONs.

DOI： 10.1248/cpb.c17-00615

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CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：生命科学系学会合同年次大会運営事務局  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We herein report the first covalent G-site-binding inhibitor for GST, GS-ESF (1), which irreversibly inhibited the GSTP1-1 function. LC-MS/MS and X-ray structure analyses of the covalently linked GST-inhibitor complex suggested that 1 reacted with Tyr108 of GSTP1-1. The mechanism of covalent bond formation was discussed based on MD simulation results.

DOI： 10.1039/c7cc05829b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

We developed a new approach for chemical ligation of oligonucleotides using the electrophilic phosphorothioester (EPT) group. A nucleophilic phosphorothioate group on oligonucleotides was converted into the EPT group by treatment with Sanger's reagent (1-fluoro-2,4-dinitrobenzene). EPT oligonucleotides can be isolated, stored frozen, and used for the ligation reaction. The reaction of the EPT oligonucleotide and an amino-modified oligonucleotide took place without any extra reagents at pH 7.0-8.0 at room temperature, and resulted in a ligation product with a phosphoramidate bond with a 39-85% yield. Thismethod has potential uses in biotechnology and chemical biology.

DOI： 10.1093/nar/gkx459

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Post-translational modification of histone tails plays critical roles in gene regulation. Thus, molecules recognizing histone tails and controlling their epigenetic modification are desirable as biochemical tools to elucidate regulatory mechanisms. There are, however, only a few synthetic ligands that bind to histone tails with substantial affinity. We report CA2 and CA3, which exhibited sub-micromolar affinity to histone tails (especially tails with a trimethylated lysine). Multivalent display of trisulfonated calix[4] arene was important for strong binding. CA2 was applicable not only to synthetic tail peptides but also to endogenous histone proteins, and was successfully used to pull-down endogenous histones from nuclear extract. These findings indicate the utility of these supramolecular ligands as biochemical tools for studying chromatin regulator protein and as a targeting motif in ligand-directed catalysis to control epigenetic modifications.

DOI： 10.1002/cbic.201500448

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A copper(I)-catalyzed anomeric aminoalkynylation reaction of unprotected aldoses was realized. Use of an electron-deficient phosphine ligand, boric acid to stabilize the iminium intermediate, and a protic additive (IPA) to presumably enhance reversible carbohydrate-boron complexation were all essential for efficient conversion. The reaction proceeded well even with a natural disaccharide substrate, suggesting that the developed catalytic reaction could be useful for the synthesis of glycoconjugates with minimum use of protecting groups.

DOI： 10.1021/ol401810b

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Language：English   Publishing type：Research paper (scientific journal)  

Background and Purpose Oseltamivir is the most widely prescribed anti-influenza medication. However, in rare instances, it has been reported to stimulate behavioural activities in adolescents. The goal of this study was to determine the molecular mechanism responsible for these behavioural activities. Experimental Approach We performed an in vitro assay of MAO-A, the enzyme responsible for neurotransmitter degradation, using either the active form - oseltamivir carboxylate (OC) or the inactive prodrug - oseltamivir ethyl ester (OEE). We also analysed the docking of MAO-A with OEE or OC in silico. Mouse behaviours after OEE or OC administration were monitored using automated video and computer analysis. Key Results OEE, but not OC, competitively and selectively inhibited human MAO-A. The estimated Ki value was comparable with the Km values of native substrates of MAO-A. Docking simulations in silico based on the tertiary structure of MAO-A suggested that OEE could fit into the inner pocket of the enzyme. Behavioural monitoring using automated video analysis further revealed that OEE, not OC, significantly enhanced spontaneous behavioural activities in mice, such as jumping, rearing, sniffing, turning and walking. Conclusions and Implications Our multilevel analyses suggested OEE to be the cause of the side effects associated with oseltamivir and revealed the molecular mechanism underlying the stimulated behaviours induced by oseltamivir in some circumstances. © 2013 The Authors. British Journal of Pharmacology © 2013 The British Pharmacological Society.

DOI： 10.1111/bph.12102

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KOREAN CHEMICAL SOC  

Two types of resin-conjugated Tamiflu analogs were synthesized by modifying our original synthetic route of oseltamivir phosphate (Tamiflu). The prepared resins bound to influenza virus neuraminidase, the main target of Tamiflu. The resins will be useful for isolating and identifying presumed endogenous vertebrate proteins that interact with Tamiflu, which might relate to the rarely observed abnormal behavior exhibited by some influenza patients treated with Tamiflu.

DOI： 10.5012/bkcs.2010.31.03.588

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A resin linked with the Tamiflu core was synthesized by modifying our original synthetic route Of oseltamivir phosphate (Tamiflu). The prepared resin bound to the influenza virus enzyme neuraminidase, the main target of Tamiflu. The immobilized Tamiflu analog will be useful for isolating and identifying presumed endogenous vertebrate proteins that interact with Tamiflu, which might relate to the abnormal behavior exhibited by some influenza patients treated with Tamiflu. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2009.01.142

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.200804777

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：生命科学系学会合同年次大会運営事務局  

Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：(公社)日本薬学会  

J-GLOBAL

Language：Japanese   Publisher：(公社)日本薬学会  

J-GLOBAL