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Results 251 - 300 of 999
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Xu Lei - - 2011
Nucleic acids were found to partition into the phenol phase during phenol extraction in the presence of guanidinium at certain concentrations under acidic conditions. The guanidinium-concentration-dependent nucleic acid partitioning patterns were analogous to those of the nucleic acid adsorption/partitioning onto silica mediated by guanidinium, which implied that phenol and silica ...
Bai Yugang - - 2011
Linear hybrid block copolymers with well controlled molecular weights and narrow polydispersities were synthesized via ring-opening metathesis polymerization (ROMP) followed by ring-opening polymerization of amino acid N-carboxyanhydrides.
Dunlap Norma - - 2011
An efficient approach to novel cyclopropyl peptidomimetics has been developed. The synthetic route involves a cyclopropanation using ethyl (dimethylsulfuranylidene)acetate (EDSA) as the key step and affords a cyclopropyl peptidomimetic core in three steps from protected amino acid Weinreb amides.
Nangreave Ryan C - - 2011
Tandemly activated tRNAs participate effectively in protein synthesis and exhibit superior chemical and biochemical stability compared to the more commonly used singly aminoacylated tRNAs. While several bisaminoacylated tRNAs have been prepared via the T4 RNA ligase-mediated condensation of bisaminoacylated pdCpAs and abbreviated tRNA transcripts (tRNA-C(OH)), the bisaminoacylated pdCpAs are difficult ...
Reenabthue Nisanath - - 2011
Conformationally restricted pyrrolidinyl PNAs with an α/β-dipeptide backbone consisting of a nucleobase-modified proline and a cyclic five-membered amino acid spacer such as (1S,2S)-2-aminocyclopentanecarboxylic acid (ACPC) (acpcPNA) can form very stable hybrids with DNA with high Watson-Crick base pairing specificity. This work aims to explore the effect of incorporating 3-aminopyrrolidine-4-carboxylic acid ...
Cowley Andrew R - - 2011
The synthesis and likely conformational structure of rigid spirocyclic bislactams and lactam-lactones derived from pyroglutamic acid, and their suitability as lead structures for applications in drug development programmes using cheminformatic analysis, has been investgated.
Karthikeyan Jaganathan - - 2011
A cobalt-catalyzed addition of aryl- and alkenylboronic acids to aldehydes and phthalaldehyde to give the corresponding biarylketones and 3-aryl phthalides in good to excellent yields in one pot is described.
Chebanov Valentin A - - 2011
New and high regioselective method of the synthesis of 2,7-diaryl-4,7-dihydropyrazolo[1,5-a]pyrimidine-5-carboxylic acids by reaction of 3-aryl-5-aminopyrazoles with arylidenpyruvic acid at room temperature under ultrasonication was developed and discussed.
Lee Jaewoo - - 2011
Dead and dying cells release nucleic acids. These extracellular RNAs and DNAs can be taken up by inflammatory cells and activate multiple nucleic acid-sensing toll-like receptors (TLR3, 7, 8, and 9). The inappropriate activation of these TLRs can engender a variety of inflammatory and autoimmune diseases. The redundancy of the ...
Hjelmgaard Thomas - - 2011
The development of a highly efficient methodology for solid-phase synthesis of para- and meta-arylopeptoids (oligomeric N-substituted aminomethyl benzamides) with free acids or free amides at the C-terminus is described. The arylopeptoids were synthesised by means of a convenient submonomer protocol in which the arylopeptoid residues were created in an iterative ...
Katz Ehud - - 2011
Label-free LC-MS/MS-based shot-gun proteomics was used to quantify the differential protein synthesis and metabolite profiling in order to assess metabolic changes during the development of citrus fruits. Our results suggested the occurrence of a metabolic change during citrus fruit maturation, where the organic acid and amino acid accumulation seen during ...
Antonczak Alicja K - - 2011
There are many approaches to introduce non-native functionality into proteins either translationally or post-translationally. When a noncanonical amino acid (NAA) is incorporated translationally, the host organism's existing translational machinery is relied upon to insert the amino acid by the same well-established mechanisms used by the host to achieve high fidelity ...
de Beer Roseri J A C - - 2011
The substrate mimetics approach is a versatile method for small-scale enzymatic peptide-bond synthesis in aqueous systems. The protease-recognized amino acid side chain is incorporated in an ester leaving group, the substrate mimetic. This shift of the specific moiety enables the acceptance of amino acids and peptide sequences that are normally ...
Rajak Harish - - 2011
The enzymatic inhibition of histone deacetylase activity has come out as a novel and effectual means for the treatment of cancer. Two novel series of 2-[5-(4-substitutedphenyl)-[1,3,4]-oxadiazol/thiadiazol-2-ylamino]-pyrimidine-5-carboxylic acid (tetrahydro-pyran-2-yloxy)-amides were designed and synthesized as novel hydroxamic acid based histone deacetylase inhibitors. The antiproliferative activities of the compounds were investigated in vitro ...
Trevino Simon G - - 2011
Multiple lines of evidence support the hypothesis that the early evolution of life was dominated by RNA, which can both transfer information from generation to generation through replication directed by base-pairing, and carry out biochemical activities by folding into functional structures. To understand how life emerged from prebiotic chemistry we ...
Gao Chao - - 2011
Chemoenzymatic synthesis of N-acetyl-d-neuraminic acid from N-acetyl-d-glucosamine using the spore surface-displayed N-acetyl-d-neuraminic acid aldolase at a high concentration (53.9 g liter(-1)) was achieved in this study. Thus, displaying a target enzyme on the surface of spores might be an alternative for integration of biocatalytic conversion into chemical synthesis.
Nimesh Surendra - - 2011
The design and development of nucleic acids based therapeutics for the treatment of diseases arising from genetic abnormalities has made significant progress over the past few years. Advances in synthetic oligonucleotide chemistry resulted in synthesis of nucleic acids that are relatively stable in in vivo environments. However, cellular targeting and ...
Reginato Gianna - - 2011
An efficient synthesis of various protected syn-β-sulfenyl amides is described. These are prepared from the corresponding enantiopure amino allylsilanes which are in turn obtained from naturally occurring amino acids. The key step for introduction of the sulfur substituent is a diastereoselective electrophilic sulfodesilylation which is carried out with phthalimidesulfenyl chloride. ...
Milanese Alberto - - 2011
6[3-(1-Adamantyl)-4-methoxyphenyl]-2-naphthoic acid (Adapalene®), a synthetic aromatic retinoid specific for RARβ and RARγ receptors, has been prepared utilizing a Pd/C-mediated Suzuki coupling between 6-bromo-2-naphthoic acid and 4-methoxyphenyl boronic acid, followed by introduction of an adamantyl group in the position 3 of the formed 6-(4-methoxyphenyl)-2-naphthoic acid. The interaction of 6-(4-methoxyphenyl)-2-naphthoic acid/ethyl ester ...
Gouault Nicolas - - 2011
The enantiospecific syntheses of pyridinones from amino acids via a gold-catalyzed strategy are reported. Excellent stereocontrol was observed during the cyclization. This approach provides a straightforward tool for further synthetic applications toward piperidines.
Erives Albert - - 2011
All living organisms encode the 20 natural amino acid units of polypeptides using a universal scheme of triplet nucleotide "codons". Disparate features of this codon scheme are potentially informative of early molecular evolution: (i) the absence of any codons for D-amino acids; (ii) the odd combination of alternate codon patterns ...
Iwayama Yuki - - 2011
The glycan moiety of ganglioside HPG-7, isolated from the sea cucumber (Holothuria pervicax), was synthesized for the first time. The characteristic substructure, a trisialic acid sequence embedded in the glycan, was deliberately constructed by utilizing suitably differentiated sialyl units for various synthetic purposes. Finally, a pentasaccharide was successfully delivered as ...
Zhou Xiao-Long - - 2011
Aminoacyl-tRNA synthetases (aaRSs) are remarkable enzymes that are in charge of the accurate recognition and ligation of amino acids and tRNA molecules. The greatest difficulty in accurate aminoacylation appears to be in discriminating between highly similar amino acids. To reduce mischarging of tRNAs by non-cognate amino acids, aaRSs have evolved ...
Kosaki Yusuke - - 2011
An aldol reaction followed by elimination of the derived mesylate was used to construct the side chain that was designed to afford the cyclohexene ring of coronafacic acid via intramolecular alkylation. Elimination of the mesylate proceeded with TBAF. The alkylation was achieved with t-BuOK in THF, and then hydrolysis afforded ...
Czifrák Katalin - - 2011
O-Peracetylated or -perbenzoylated C-(1-bromo-1-deoxy-d-glycopyranosyl)formamides of d-gluco, d-galacto, and d-arabino configuration were reacted with Ag(I)-salts or HgO in nitrile solvents to give N-acyl-1-cyano-d-glycopyranosylamines with an axial C-N bond at the anomeric centre. In the presence of HgBr(2), Hg(CN)(2), or InCl(3) the anomer of the above glycosylamine with an equatorial C-N bond ...
Lin Daizong - - 2011
A new β-amino acrylic acid Ni(II) complex has been developed and used for the synthesis of α-alkyl-β-amino acids via alkylation with alkyl halides under operationally convenient conditions. The pivotal α-alkylated intermediate can be converted into the corresponding α-alkyl-β-amino acids via two steps with a wide range of substituents.
Hogendorf Wouter F J - - 2011
This communication describes the first automated solid phase synthesis of teichoic acids (TAs) and the preparation by this method of a number of well-defined TA structures, which were probed for their antigenicity. An opsonophagocytic killing assay revealed a clear TA-length-activity relationship and indicated a promising candidate for future vaccine development.
Xiang Zheng Z The Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, - - 2011
Fluorescent unnatural amino acids (UAAs), when genetically incorporated into proteins, can provide unique advantages for imaging biological processes in vivo. Synthesis of optically pure L-enantiomer of fluorescent UAAs is crucial for their effective application in live cells. An efficient six-step synthesis of L-3-(6-acetylnaphthalen-2-ylamino)-2-aminopropanoic acid (L-Anap), a genetically encodable and polarity-sensitive ...
Jafari E - - 2011
Quinazolinones are interesting molecules with a wide range of biological activities. We prepared a number of quinazolinone derivatives by the condensation of 5-bromo- or 5-nitro-substituted anthranilic acids with chloro-acyl chlorides. Anthranilic acid derivatives were treated with either 3-chloro-propionyl chloride or 4-chloro-butyryl chloride to yield the corresponding N-acyl-anthranilic acids. The resultants ...
Baboota Sanjula - - 2011
Betamethasone dipropionate (BD) has anti-inflammatory, immunomodulatory, and antiproliferative activity. The aim of the current work was to test the hypothesis that the addition of corticosteroid such as BD and a keratolytic agent such as salicylic acid in nanocarrier based microemulsions formulation would result in enhancement and sustaining of corticosteroid delivery ...
Nuñez-Villanueva Diego - - 2011
To explore further the chemistry of amino acid-derived β-lactams, their conversion to α,α-heterocyclic quaternary amino acid derivatives is investigated. The latter derivatives, containing 2-oxoazepane as the α,α-substituent, are synthesized by a simple Pd-C catalyzed hydrogenolysis of Orn(Z)-derived 2-azetidinones. The rearrangement from 4- to 7-membered lactam ring is driven by the ...
Morimoto Jumpei - - 2011
Transfer RNA (tRNA) is an essential component of the cell's translation apparatus. These RNA strands contain the anticodon for a given amino acid, and when "charged" with that amino acid are termed aminoacyl-tRNA. Aminoacylation, which occurs exclusively at one of the 3'-terminal hydroxyl groups of tRNA, is catalyzed by a ...
Fante Cristina - - 2011
Dopamine has previously been shown to inhibit angiogenesis in vitro and in vivo, but its clinical applications in this context are severely limited by its short half-life. Here we report the synthesis of a polyglutamic acid-dopamine conjugate and show that conjugation significantly extends (from 1 to 24 h) dopamine's antiangiogenic ...
Song Xiao-Ping - - 2011
Previous studies have demonstrated that some selected amino monoacids and amino diacids can function as leaving groups in the polymerase-catalyzed incorporation of deoxynucleotides into DNA. Among these, the iminodiacetic acid phosphoramidate of deoxyadenosine monophosphate (IDA-dAMP) represents an interesting example, as it could overcome some of the problems observed when using ...
Ellamar Joel B - - 2011
Furan fatty acids (F-acids) gain special attentions since they are known to play important roles in biological systems including human. Specifically F-acids are known to have strong antioxidant activity like radical scavenging activity. Although widely distributed in most biological systems, F-acids are trace components and their biosynthesis are complicated and ...
Grim Joseph C JC Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, - - 2011
A divergent synthesis of (-)-4-epi-shikimic acid was developed. This route features a one-pot zinc-mediated reductive ring opening of an arabinofuranose followed by a Barbier reaction and culminates in a ring-closing metathesis. Functionalization of (-)-4-epi-shikimic acid via conjugate addition of a thiol occurs in high diastereoselectivity to afford a product with ...
Zhang Yingjie - - 2011
Histone deacetylases (HDACs) are a promising target for treating cancer and some other disorders. Herein, based on the structure of our previously reported tetrahydroisoquinoline-based hydroxamic acids, a novel series of tyrosine-based hydroxamic acid derivatives was designed and synthesized as HDACs inhibitors. Compared with tetrahydroisoquinoline-based hydroxamic acids, tyrosine-based hydroxamic acid derivatives ...
Jiang Jian-Ming - - 2011
PBDTBO, a conjugated polymer comprising benzo[1,2-b:4,5-b']dithiophene (BDT) and 5,6-bis(octyloxy)benzo[c][1,2,5]oxadiazole (BO) units, exhibits a deep HOMO energy level of -5.27 eV and excellent solubility. A device incorporating PBDTBO and [6,6]-phenyl-C(61)-butyric acid methyl ester (1 : 1, w/w) exhibited a power conversion efficiency of 5.7%.
Vasantha B - - 2011
Synthesis of N(α)-protected amino acyl azides starting from corresponding acids via the carbonyldiimidazole (CDI) activation is described. The protocol is extended for a one-pot preparation of ureido peptides that circumvents the isolation of acyl azide and isocyanate intermediates. The reaction was accomplished without using any additives and base. The protocol ...
Roviello Giovanni N - - 2011
In this work, we report a technological approach to a novel Fmoc-protected nucleoamino acid, based on l-tyrosine, carrying the DNA nucleobase on the hydroxyl group by means of an ester bond, suitable for the solid-phase synthesis of novel aromatic nucleopeptides of potential interest in biomedicine. After ESI-MS and NMR characterization ...
Zhou Dan D Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, - - 2011
Amino acid response (AAR) pathway is activated when cells are deprived of amino acids. In the present study, using the human colon cancer cell line SW480, we observed that DKK1, an antagonist of the Wnt pathway, was significantly induced at the mRNA level after the removal of amino acids from ...
Chuang Hui-Yen - - 2011
We established a HT-29/tk-luc human colorectal carcinoma-bearing animal model for the study of the inhibition effect and mechanism of orlistat, a fatty acid synthase (FASN) inhibitor. The results showed that orlistat caused cell cycle arrest at G1 phase, and triggered apoptosis through caspase-3 activation. The tumor inhibition effect of orlistat ...
Jakubowski Hieronim - - 2011
All living organisms conduct protein synthesis with a high degree of accuracy maintained in the transmission and flow of information from a gene to protein product. One crucial "quality control" point in maintaining a high level of accuracy is the selectivity by which aminoacyl-tRNA synthetases furnish correctly activated amino acids, ...
Barrett Lee - - 2011
Metallic nanoparticles functionalized with oligonucleotides are used for a number of nucleic acid detection strategies. However, oligonucleotide-nanoparticle conjugates suffer from a lack of stability when exposed to certain conditions associated with DNA detection assays. In this study, we report the synthesis of thiol and thioctic acid-modified oligonucleotide gold nanoparticle (OGNs) ...
Robertson Daniel Stewart - - 2011
Abstract Biochemical reactions in cells which involve oxalic acid are described. It is shown that this compound is required for the formation of uracil and orotic acid. The former is a component of RNA which is common to all cells in the human metabolism. On the basis of the biochemical ...
Fowler Lindsay S - - 2011
The first stereoselective synthesis of 2,6-trans-6-substituted-4-oxo-l-pipecolic acids using a tandem reductive amination/6-endo-trig cyclisation process is described. The sequential reduction and cyclisation mediated by sodium cyanoborohydride allowed the preparation of a series of highly functionalised 6-alkyl and 6-aryl analogues.
Ogris Manfred - - 2011
Nucleic acids offer the possibility of tailor made, individualized treatments for genetic disorders, infectious diseases and cancer. As an alternative to viral vectors, synthetic delivery systems have a potentially improved safety profile, but often lack sufficient efficiency especially when applied in vivo. Receptor targeting of synthetic vectors can improve the ...
Sie Karen K Y - - 2011
Background Intrauterine and early life exposure to folic acid has significantly increased in North America owing to folic acid fortification, widespread supplemental use and periconceptional folic acid supplementation. The effect of maternal and postweaning folic acid supplementation on colorectal cancer risk in the offspring was investigated. Methods Female rats were ...
Yao Kun - - 2011
The in vivo anti-thrombotic activities of amino acid modified tetrahydro-β-carbolines depended upon the proximity of the side chain of the amino acid residue to the carboline-cycle. Based on this proximity the computerized screening of various tetrahydro-β-carboline derivatives was performed and N-[(1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carbonyl]-N'-(amino-acid-acyl)hydrazines were explored having large proximity. The in vivo anti-thrombotic assays explored ...
Herath Kithsiri - - 2011
Protein synthesis can be estimated by measuring the incorporation of a labeled amino acid into a proteolytic peptide. Although prelabeled amino acids are typically administered, recent studies have tested (2)H(2)O; the assumption is that there is rapid equilibration of (2)H (in body water) with the carbon-bound hydrogens of amino acids ...
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