- Enhanced Mechanical and Helical Properties with Achiral Calix[4]arene in a Co-Assembled Hydrogel with a Helical Structure
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A mixture of the building blocks 1A and 2G, featuring d-alanine moieties and glycine-functionalized calix[4]arene moieties, respectively, formed a co-assembled hydrogel. In particular, the remarkable enhancement of helical intensity of co-assembled gel was controlled by achiral calix[4]arene 2G, which was attributed to the bridging effect between 1A and 2G, similar to a helical structure. Furthermore, the improvement of the mechanical strength (G′ and G′′ values) of the co-assembled hydrogel prepared with 1.0 equivalent of 2G were around 7000 % and 4400 % stronger, respectively, compared to the gel prepared from the 0.25 equivalents of 2G. The improved mechanical strength was attributed to the formation of a network structure with a H-bonding interaction between 1A and 2G. The results indicate that the enhanced helical and mechanical strength of the co-assembled gel could be controlled by achiral component 2G.
- Choi, Heekyoung,Seo, Hyowon,Go, Misun,Lee, Shim Sung,Jung, Jong Hwa
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- A novel prodrug of salicylic acid, salicylic acid-glycylglycine conjugate, utilizing the hydrolysis in rabbit intestinal microorganisms
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The hydrolysis of salicylic acid-glycylglycine conjugate (salicyl-glycylglycine) following oral, intravenous, intracaecal and rectal administration (434, 72, 36 and 36 μmol kg -1, respectively: equivalent to salicylic acid) was examined in rabbits to develop a novel prodrug of salicylic acid. Salicylic acid was detected in thc blood 2 h after oral administration of salicyl-glycylglycine and it reached a maximum level (55-6 μg mL -1) at 15 h, whereas a small amount of salicyl-glycylglycine was found in the blood. In contrast, unchanged salicyl-glycylglycine was found mainly in the blood following its intravenous administration suggesting the involvement of presystemic deconjugation in the hydrolysis of salicyl-glycylglycine. Immediate and very extensive salicyclic acid formation in the caecum was observed following intracaecal administration of salicyl-glycylglycine, suggesting that the intestinal microorganisms were responsible for the biotransformation of this compound. In-vitro incubation of salicyl-glycylglycine with caecal content showed that salicyl-glycylglycine was hydrolysed efficiently in the caecum. Consequently, the blood concentration ol salicylic acid was prolonged extensively following rectal administration of salicyl-glycylglycine, indicating the usefulness of salicyl-glycylglycine as a prodrug of salicylic acid.
- Nakamura,Asai,Nishida,Sasaki
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- Mitochondria-targeting oxidovanadium(IV) complex as a near-ir light photocytotoxic agent
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Oxidovanadium(IV) complexes [VO(L1)(phen)]×Cl (1) and [VO(L2)(L3)]×Cl (2), in which HL1 is 2-{[(benzimidazol-2-yl)methylimino]-methyl}phenol (sal-ambmz), HL2 is 2-[({1-[(anthracen-9-yl)methyl]-benzimi
- Prasad, Puja,Khan, Imran,Kondaiah, Paturu,Chakravarty, Akhil R.
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- Novel thiazolidinedione-5-acetic-acid-peptide hybrid derivatives as potent antidiabetic and cardioprotective agents
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Thiazolidinediones (TZDs) are one of the important clinically established antidiabetic agents. Amino-acid and peptides have an advantage of better target selectivity and specificity. As hybrids, they also improved absorption and showed better bioavailability, which in turn makes them safer. Hence, here an effort has been made to synthesize hybrids of thiazolidinedione with amino-acids and peptides and evaluate their antidiabetic and cardioprotective effect in streptozotocin-nicotinamide (STZ-NA) induced Type 2 diabetes mellitus (T2DM) rat models. A series of 14 thiazolidinedione-5-acetic acid hybrids with of different amino-acids and peptide combinations were synthesized, characterized and further screened for antidiabetic and cardioprotective activity. Among all, six compounds T1 (SSDMA1), T4 (SSDMA4), T5 (SSDMA5), T7 (SDMA13), T9 (SSDMA15) and T13 (SSDMA49) showed better antioxidant activity and comparable % glucose uptake by yeast cells. Hence, the in vivo antidiabetic screening was done for these six compounds. Among all six T1, T7, T13 showed significant blood glucose level decrease compared to standard pioglitazone HCl. Also T1, T7 and T13 showed better antioxidant activity with lower IC50 value than standard ascorbic acid, and hence in vivo cardioprotective studies were done for these. The ECG studies showed that T1 (SSDMA1) and T7 (SSDMA13) were better effective than SDMA49 (T13) in restoring the normal functioning of the heart, thus may help in preventing the development of diabetic cardiomyopathy (DCM) and controlling T2DM.
- Maji,Samanta
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p. 1163 - 1172
(2017/02/23)
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- The discovery of allyltyrosine based tripeptides as selective inhibitors of the HIV-1 integrase strand-transfer reaction
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From library screening of synthetic antimicrobial peptides, an O-allyltyrosine-based tripeptide was identified to possess inhibitory activity against HIV-1 integrase (IN) exhibiting an IC50 value of 17.5 μM in a combination 3′-processing and strand transfer microtitre plate assay. The tripeptide was subjected to structure-activity relationship (SAR) studies with 28 peptides, incorporating an array of natural and non-natural amino acids. Resulting SAR analysis revealed the allyltyrosine residue was a key feature for IN inhibitory activity whilst incorporation of a lysine residue and extended hydrophilic chains bearing a terminal methyl ester was advantageous. Addition of hydrophobic aromatic moieties to the N-terminal of the scaffold afforded compounds with improved inhibitory activity. Consolidation of these functionalities lead to the development of the tripeptide 96 which specifically inhibited the IN strand-transfer reaction with an IC50 value of 2.5 μM.
- Dalton, Neal,Gordon, Christopher P.,Boyle, Timothy P.,Vandegraaf, Nicholas,Deadman, John,Rhodes, David I.,Coates, Jonathan A.,Pyne, Stephen G.,Keller, Paul A.,Bremner, John B.
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supporting information
p. 6010 - 6023
(2016/07/06)
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- Synthesis of [12]aneN3-dipeptide conjugates as metal-free DNA nucleases
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In this Letter, a series of macrocyclic polyamine [12]aneN 3-dipeptide conjugates as a new type of metal-free nucleases were synthesized and fully characterized with 1H NMR, 13C NMR, IR, and HR-MS. Results indicate that th
- Li, Zhi-Fen,Chen, Hua-Long,Zhang, Li-Jun,Lu, Zhong-Lin
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supporting information; experimental part
p. 2303 - 2307
(2012/05/04)
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- Designed semisynthetic protein inhibitors of Ub/Ubl E1 activating enzymes
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(Chemical Equation Presented) Semisynthetic, mechanism-based protein inhibitors of ubiquitin (Ub) and ubiquitin-like modifier (Ubl) activating enzymes (E1s) have been developed to target E1-catalyzed adenylation and thioesterification of the Ub/Ubl C-terminus during the processes of protein SUMOylation and ubiquitination. The inhibitors were generated by intein-mediated expressed protein ligation using a truncated Ub/Ubl protein (SUMO residues 1-94; Ub residues 1-71) with a C-terminal thioester and synthetic tripeptides having a C-terminal adenosine analogue and an N-terminal cysteine residue. SUMO-AMSN (4a) and Ub-AMSN (4b) contain a sulfamide group as a nonhydrolyzable mimic of the phosphate group in the cognate Ub/Ubl-AMP adenylate intermediate in the first half-reaction, and these constructs selectively inhibit SUMO E1 and Ub E1, respectively, in a dose-dependent manner. SUMO-AVSN (5a) and Ub-AVSN (5b) contain an electrophilic vinyl sulfonamide designed to trap the incoming E1 cysteine nucleophile (Uba2 Cys173 in SUMO E1; Uba1 Cys593 in Ub E1) in the second half-reaction, and these constructs selectively, covalently, and stably cross-link to SUMO E1 and Ub E1, respectively, in a cysteine nucleophile-dependent manner. These inhibitors are powerful tools to probe outstanding mechanistic questions in E1 function and can also be used to study the biological functions of E1 enzymes. Copyright
- Lu, Xuequan,Olsen, Shaun K.,Capili, Allan D.,Cisar, Justin S.,Lima, Christopher D.,Tan, Derek S.
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supporting information; experimental part
p. 1748 - 1749
(2010/04/25)
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- Novel glycine like amino acids from glyco-α-aminonitriles as building blocks for peptide synthesis
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Our interest in the glycoaminocyanation reaction led us to apply this methodology to introduce amino acids on a monosaccharide using the N-terminal position. The GAAs described in this paper are characterized by having the amino and carboxylic acid functionalities on a disubstituted position of the saccharide backbone leading to α,α-disubstituted glycines. These new sugar amino acids showed a restricted conformation involving a spontaneous intramolecular cyclization between the C- and N-terminal positions during hydrolysis or hydrogenolysis to give the corresponding oxopiperazine. Tripeptide mimics were obtained by the introduction of an additional amino acid using one-pot conditions starting from these cyclic by-products under basic media. We demonstrated that these pseudo tripeptides are good candidates for extension of the peptidic scaffold and cyclization.
- Ducatel, Helene,Van Nhien, Albert Nguyen,Postel, Denis
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- Synthesis of the C-Therminal Dodecapeptide of the Human Fibrinogen γ-Chain
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The C-terminal dodecapeptide His-His-Leu-Gly-Gly-Ala-Lys-Gln-Ala-Gly-Asp-Val (12) of the human fibrinogen γ-chain was synthesized by condensation of segments, and >> according to Scheme 1.The α-benzyloxycarbonyl-ω-t-butyl system w
- Masiukiewicz, E.,Rzeszotarska, B.,Szczerbaniewicz, J.,Cierniewski, Cz.
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p. 1035 - 1041
(2007/10/02)
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