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Results 201 - 250 of 1658
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Joly Kévin M - - 2010
Isolipoic acid, a symmetrical and achiral isomer of the commonly used alpha-lipoic acid, has previously been overlooked as a tether group for the formation of self-assembled monolayers (SAMs). Here its ready synthesis through a new route and its functionalization with ferrocenyl groups for redox-active SAM formation on gold electrodes are ...
Sikora Jakub - - 2010
Human acid alpha-glucosidase (GAA, EC 3.2.1.20) is a lysosomal enzyme that belongs to the glycoside hydrolase family 31 (GH31) and catalyses the hydrolysis of alpha-1,4- and alpha-1,6-glucosidic linkages at acid pH. Hereditary deficiency of GAA results in lysosomal glycogen storage disease type II (GSDII, Pompe disease). The aim of this ...
Wang Yanyan - - 2010
The carbohydrate-derived lipoic acid derivatives were studied as protein and cell resistant biomaterials. Six types of carbohydrates were examined for their abilities to reduce nonspecific adsorption of human serum and Hela cell using quartz crystal microbalance. Our data suggested that the structures of carbohydrates play an important role in resisting ...
O'Reilly Elaine - - 2010
An atom-efficient and stereoselective synthesis has been developed for the preparation of alpha-2H-labelled (S)-alpha-amino acids, starting from a novel chiral diketopiperazine scaffold. Efficient mono-alkylation of the chiral template afforded the (S)-substituted adducts with the nature of the electrophile significantly effecting the stereochemical outcome. Subsequent alkylation was totally selective producing the ...
Martelli Gianluca - - 2010
The N-tosyl carbamates 4a-e, easily prepared starting from the Baylis-Hillman adducts 3a-e, underwent cyclization carried out with I(2)/NIS in the presence of NaH, to give the corresponding 2-oxo-1,3-oxazolidines 5a-e in good yield and total stereoselection when the substituent at C-5 is Ar. After the removal of tosyl group, followed by ...
Sozio Piera - - 2010
Current evidences support the hypothesis that non-steroidal anti-inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimer's disease (AD). In the present work, our attention was focused on ibuprofen (IBU) used in clinical trails to prevent Alzheimer's disease, and (R)-alpha-lipoic acid (LA) considered as a potential neuroprotective ...
Grzywa Renata - - 2010
A series of new aromatic monoesters of alpha-aminoaralkylphosphonic acids were synthesized by selective hydrolysis of corresponding aromatic diesters of alpha-aminoaralkylphosphonic acids. New potential inhibitors of aminopeptidase N/CD13, an enzyme important in tumour angiogenesis, were developed. Some derivatives of the homophenylalanine and norleucine related monoaryl phosphonates displayed higher inhibition potency than ...
G D Xiang - - 2010
Many studies showed that impairment of flow-mediated endothelium-dependent arterial dilation (FMD) exists in patients with subclinical hypothyroidism (sHT). The crucial mechanism of this endothelial dysfunction remain unclear. We hypothesized that oxidative stress may be partially responsible for the impairment in FMD in patients with sHT. Thus, the present study was ...
Amaral Alexandre Umpierrez - - 2010
Patients affected by maple syrup urine disease (MSUD) present severe neurological symptoms and brain abnormalities, whose pathophysiology is poorly known. In the present study we investigated the in vitro effects of leucine (Leu), alpha-ketoisocaproic acid (KIC) and alpha-hydroxyisovaleric acid (HIV), respectively, the branched-chain amino, keto and hydroxy acids that most ...
Yamashita Mana - - 2010
Readily available cinnamic acid derivatives such as ferulic acid couple with beta-bromostyrenes and 1-bromo-4-phenylbutadiene under palladium catalysis accompanied by decarboxylation to produce the corresponding alpha,omega-diarylbutadienes and -hexatrienes, respectively. Some of the products exhibit solid-state fluorescence.
Kumar J Sravan - - 2010
An efficient methodology for the preparation of alpha-hydroxyamides via boric acid mediated addition of isonitriles on to aldehydes has been developed. The reaction of isonitriles with alpha-boronobenzaldehyde takes place under intramolecular catalysis conditions to provide functionalized benzoxaboroles.
Lou Xiaoding - - 2010
A new indirect approach to explore sensitive colorimetric sensors toward alpha-amino acids is proposed: the pink solution of 1 and copper ions changed to colorless immediately upon the addition of alpha-amino acids. As the hydrolysis of bovine serum albumin (BSA) with the aid of trypsin produces alpha-amino acids, the complex ...
Selim Nabila S - - 2010
The effects of gamma rays (25, 50 and 100 Gy) on stored erythrocytes were studied by measuring their dielectric properties and observing their morphology under scanning electron microscopy. Alpha lipoic acid (a potent natural antioxidant) was introduced prior to irradiation for radioprotection. It can be concluded that the dose level ...
Jin Shan - - 2010
Fluorescent boronic acids are very useful for the design and synthesis of carbohydrate sensors. In an earlier communication, we first described the effort of developing water soluble fluorescent alpha-amidoboronic acids, which change fluorescence upon sugar binding. In this report, we describe a general method of functionalizing such boronic acids and ...
Struys Eduard A - - 2010
The mammalian degradation of lysine is believed to proceed via two distinct routes, the saccharopine and the pipecolic acid routes, that ultimately converge at the level of alpha-aminoadipic semialdehyde (alpha-AASA). alpha-AASA dehydrogenase-deficient fibroblasts were grown in cell culture medium supplemented with either L-[alpha-(15)N]lysine or L-[epsilon-(15)N]lysine to explore the exact route ...
Li Han - - 2010
The biological production of fuels from renewable sources has been regarded as a feasible solution to the energy and environmental problems in the foreseeable future. Recently, the biofuel product spectrum has expanded from ethanol and fatty acid methyl esters (biodiesel) to other molecules, such as higher alcohols and alkanes, with ...
Serrano-Ruiz Juan Carlos - - 2010
Lignocellulosic biomass is renewable and cheap, and it has the potential to displace fossil fuels in the production of fuels and chemicals. Biomass-derived carboxylic acids are important compounds that can be used as platform molecules for the production of a variety of important chemicals on a large scale. Lactic acid, ...
Senoo Akihiro - - 2010
L-Amino acid alpha-ligase (Lal), catalyzing the formation of alpha-dipeptides from unprotected L-amino acids in an ATP-dependent manner, is used in cost-effective fermentative production of dipeptides. We searched for novel Lals by in silico screening using Hidden Markov Model-based profile analysis, and identified five novel Lals that showed low similarity and ...
Al-Attar Atef M - - 2010
The present study was designed to evaluate the influence of alpha-lipoic acid treatment in rats exposed to malathion. Forty adult male rats were used in this study and distributed into four groups. Animals of group 1 were untreated and served as control. Rats of group 2 were orally given malathion ...
Intelmann Daniel - - 2009
Besides undesirable changes in the attractive aroma, a significant decrease in the intensity of the bitterness as well as a change of the taste into a lingering, harsh bitterness has long been known as a shelf-life limiting factor of beer. Multiple studies have demonstrated that the aging of beer induces ...
Sambasivan Sunderraman - - 2010
Chiral discrimination of alpha-amino acids has been realized by a C(2)-symmetric homoditopic receptor, which is based on a binaphthyl chiral skeleton with 2,2'diisopropoxy substituents and a common binding side arm, (o-carboxamido)-trifluoroacetophenone moiety, in the 3,3'-positions, which recognizes alpha-amino acids as their amino carboxylate forms through formation of stabilized adducts.
Intelmann Daniel - - 2009
The typical bitterness of fresh beer is well-known to decrease in intensity and to change in quality with increasing age. This phenomenon was recently shown to be caused by the conversion of bitter tasting trans-iso-alpha-acids into lingering and harsh bitter tasting tri- and tetracyclic degradation products such as tricyclocohumol, tricyclocohumene, ...
Hazelwood Lucie A - - 2010
The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop alpha-acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso-alpha-acids have hitherto been restricted to lactic acid bacteria. The present study investigated molecular ...
Guzman Marcelo I - - 2009
A reductive tricarboxylic acid (rTCA) cycle could have fixed carbon dioxide as biochemically useful energy-storage molecules on early Earth. Nonenzymatic chemical pathways for some steps of the rTCA cycle, however, such as the production of the alpha-ketocarboxylic acids pyruvate and alpha-ketoglutarate, remain a challenging problem for the viability of the ...
Kodera Tomohiro - - 2009
The unique function of 4-hydroxyisoleucine (4-HIL) is to stimulate glucose-induced insulin secretion in a glucose-dependent manner. 4-HIL is distributed only in certain kinds of plants and mushrooms, but the biosynthetic mechanism of 4-HIL has not been elucidated. Moreover, 4-HIL-producing microorganisms have not been reported. l-isoleucine (l-Ile) hydroxylating activity producing 4-HIL ...
Ju Xin - - 2010
Substrate-directed screening was carried out to find bacteria that could deacylate O-acetylated mandelic acid from environmental samples. From more than 200 soil isolates, we identified for the first time that Pseudomonas sp. ECU1011 biocatalytically deacylated (S)-alpha-acetoxyphenylacetic acid with high enantioselectivity (E > 200), yielding (S)-mandelic acid with 98.1% enantiomeric excess ...
Adisakwattana Sirichai - - 2009
Inhibition of alpha-glucosidase and alpha-amylase delays the digestion of starch and disaccharides to absorbable monosaccharides, resulting in a reduction of postprandial hyperglycemia. Finding effective mammalian alpha-glucosidase inhibitors from natural sources can be beneficial in the prevention and treatment of diabetes mellitus. We investigated the inhibitory activity of cinnamic acid derivatives ...
Fonseca I - - 2009
The photoreaction of two alpha-cinnamic acid derivatives, alpha-o-methoxy and alpha-o-ethoxy cinnamic acid, was studied by (13)C CPMAS solid-state NMR spectroscopy in order to elucidate effects of aromatic substitution and substituent size on the kinetics of the [2+2] photodimerization. The reactants and products can be clearly differentiated and a detailed spectroscopic ...
Troyer Timothy L - - 2009
A novel alpha-diazo imide reagent and its activation by strong Brønsted acid is shown to produce the product of a syn-glycolate Mannich transform with high diastereoselection.
Park Yohan - - 2009
An efficient enantioselective synthetic method for (S)-alpha-alkyl-alpha,beta-diaminopropionic acid is reported. The asymmetric phase-transfer catalytic alkylation of N(1)-Boc-2-phenyl-2-imidazoline-4-carboxylic acid tert -butyl ester in the presence of chiral quaternary ammonium catalyst gave the corresponding alkylated products (93-98% ee) which could be transformed to enantioenriched alpha-alkyl-alpha,beta-diaminopropionic acids.
Fowler Lindsay S - - 2009
The development of a facile and general method for the preparation of enone derived alpha-amino acids is described. The key step involves a Horner-Wadsworth-Emmons reaction between an aspartic acid derived beta-keto phosphonate ester and a range of aldehydes resulting in the formation of highly functionalised alpha-amino acids in good yields. ...
Poeckel Daniel - - 2009
Pirinixic acid (Wy-14,643) is an agonist of the peroxisome proliferator-activated receptor (PPAR) subtype alpha exhibiting beneficial effects in various inflammation-related processes in a slow, long-termed fashion. We recently showed that alpha-substituted pirinixic acid derivatives are agonists of PPAR alpha and act as dual inhibitors of 5-lipoxygenase (5-LO, EC 1.13.11.34) and ...
Shay Kate Petersen - - 2009
Alpha-lipoic acid (LA) has become a common ingredient in multivitamin formulas, anti-aging supplements, and even pet food. It is well-defined as a therapy for preventing diabetic polyneuropathies, and scavenges free radicals, chelates metals, and restores intracellular glutathione levels which otherwise decline with age. How do the biochemical properties of LA ...
Lee Woo Yong WY Department of Anesthesiology and Pain Medicine InJe University, Sanggyepaik Hospital, Seoul 139-707, South - - 2009
Alpha-lipoic acid (1,2-dithiolane-3-pentanoic acid; lipoic acid) is an endogenous compound used to treat pain disorders in humans, but its mechanisms of analgesic action are not well understood. Here, we show that lipoic acid selectively inhibited native Ca(V)3.2 T-type calcium currents (T-currents) and diminished T-channel-dependent cellular excitability in acutely isolated rat ...
Richard John P - - 2009
Studies of nonenzymatic electrophilic catalysis of carbon deprotonation of glycine show that pyridoxal 5'-phosphate (PLP) strongly enhances the carbon acidity of alpha-amino acids, but that this is not the overriding mechanistic imperative for cofactor catalysis. Although the fully protonated PLP-glycine iminium ion adduct exhibits an extraordinary low alpha-imino carbon acidity ...
He Panqing - - 2009
4-Hydroxyphenylpyruvate dioxygenase (HPPD) and hydroxymandelate synthase (HMS) are the only two known members of the alpha-keto acid-dependent oxygenases that adopt the fold common to the vicinal oxygen chelate superfamily of enzymes. All other oxygenases of this type have a jellyroll fold. Despite a clearly different ancestry, the salient details of ...
Stabler Sally P SP Department of Medicine and Division of Hematology, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045, USA. - - 2009
Lipoic acid is a disulfhydryl-containing compound used in clinical medicine and in experimental models as an antioxidant. We developed a stable isotope dilution capillary gas chromatography/mass spectrometry assay for lipoic acid. We assayed a panel of the metabolites of transmethylation and transsulfuration 30 min after injecting 100 mg/kg lipoic acid ...
Narendra N - - 2009
Application of the Lossen rearrangement to the synthesis of N-urethane protected alpha-peptidyl ureas and ureidopeptides is reported. The carbodiimide mediated rearrangement of N-Boc/Z/Fmoc protected alpha-amino/peptide hydroxamic acids into isocyanates and coupling of the latter with the amino acid esters/peptide esters have been accomplished in a single-pot to obtain good yields ...
Caballero Isabel - - 2009
While beer provides a very stable microbiological environment, a few niche microorganisms are capable of growth in malt, wort, and beer. The production of off-flavors and development of turbidity in the packaged product are due to the growth and metabolic activity of wild yeast, certain lactic acid bacteria (LAB) and ...
Lee Jeong-In - - 2009
Histone deacetylase (HDAC) inhibitors are gaining interest as cancer therapeutic agents. We tested the hypothesis that natural organoselenium compounds might be metabolized to HDAC inhibitors in human prostate cancer cells. Se-Methyl-L-selenocysteine (MSC) and selenomethionine are amino acid components of selenium-enriched yeast. In a cell-free system, glutamine transaminase K (GTK) and ...
Débieux Jean-Luc - - 2009
A range of N-protected-alpha-amino acyl-5,7-dinitroindolines 3a-z were prepared in good yields from commercially available N-protected-alpha-amino acids 1a-z by a two-step sequence of acylation and intramolecular amide N-arylation. Subsequent photochemical acylation of the N-protected-alpha-amino acyl-5,7-dinitroindolines 3e,g,r afforded the corresponding N-protected-alpha-amino acid amides 22e,g,r (77-92%) under mild conditions. All these reactions occurred ...
Ura Yasuyuki - - 2009
We describe the preparation and characterization of polythioesters composed of alternating alpha-amino acid and alpha-thioglycolic acid residues that undergo dynamic constitutional exchange under mild conditions. The polymers are assembled via reversible ring-opening polymerizations of 1,4-thiazine-2,5-diones and related monomers in solution-phase conditions that do not require the use of transition metal ...
Tanaka Hiroshi - - 2009
An efficient stereoselective synthesis of alpha(2,9) tetra- to disialic acids 1-3, using the 5,4-N,O-carbonyl protected thiosialoside 4, is described. The cyclic protecting group was effective for alpha-sialylation without the need for acetonitrile as the solvent. The donor 4 enabled the formation of a tetramer in excellent yield and selectivity. Deprotection ...
Kimura Kazuyoshi - - 2009
Rat Delta6 desaturase was introduced in "oleaginous" Saccharomyces cerevisiae genetically modified by the snf2 disruption, DGA1 overexpression, and LEU2 expression to improve stearidonic acid (18:4n-3 (Delta6, 9, 12, 15)) production. When this transformed yeast was cultured in the presence of 0.7 g/l alpha-linolenic acid for 7 d, 0.4 g of ...
Gallagher Renata C - - 2009
OBJECTIVE: Folinic acid-responsive seizures and pyridoxine-dependent epilepsy are two treatable causes of neonatal epileptic encephalopathy. The former is diagnosed by characteristic peaks on cerebrospinal fluid (CSF) monoamine metabolite analysis; its genetic basis has remained elusive. The latter is due to alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase deficiency, associated with pathogenic mutations in ...
Hou Wenli - - 2009
The potential antidiabetic activity of ethyl acetate extract of the leaves of Lagerstroemia speciosa (LSL) was investigated by alpha-amylase and alpha-glucosidase inhibition assay. Six pentacyclic triterpenes (oleanolic acid, arjunolic acid, asiatic acid, maslinic acid, corosolic acid and 23-hydroxyursolic acid) were isolated from LSL. Their structures were determined by spectroscopic analysis ...
Mailloux Ryan J - - 2009
Alpha-ketoglutarate (KG) is a crucial metabolite in all living organisms, as it participates in a variety of biochemical processes. We have previously shown that this keto acid is an antioxidant and plays a key role in the detoxification of reactive oxygen species (ROS). In an effort to further confirm this ...
Balducci Daniele - - 2010
A new and convenient stereocontrolled synthesis of the optically pure (S)-alpha-methyl,alpha-amino acids 6(a-d) that exploits the chiral synthon 1,4-N,N-[(S)-1-phenylethyl]-piperazine-2,5-dione (1) is described. The (S)-1-phenylethyl group, bonded to each of the N-atoms of the 2,5-diketopiperazine, acts as a chiral inductor in the first alkylation, while the steric hindrance appears to be ...
Jia Lihong - - 2009
Acrolein is a highly reactive unsaturated hazardous air pollutant of human health concern, particularly as a component of cigarette smoke. In this study, the effects of acrolein on mitochondrial damage in IMR-90 (a human lung fibroblast cell line), and the reduction of this damage by R-alpha-lipoic acid were examined. Our ...
Liang Chien-Fu - - 2009
A new approach for the synthesis of S-linked alpha(2-->9) oligosialic acids was developed by using an asymmetric tert-butyl disulfide linkage as an anomeric thiol protecting group. Compared with conventional thiosialosides, the asymmetric disulfide sialosides can tolerate the conditions under which functional groups are modified without producing the undesired elimination and ...
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