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Results 201 - 250 of 1678
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Holz Martina - - 2011
The yeast Yarrowia lipolytica is one of the most intensively studied "non-conventional" yeast species. Its ability to secrete various organic acids, like pyruvic (PA), citric, isocitric, and alpha-ketoglutaric (KGA) acid, in large amounts is of interest for biotechnological applications. We have studied the effect of the alpha-ketoglutarate dehydrogenase (KGDH) complex ...
Luo Yong-Chun - - 2010
Amino acids are one of the most important classes of the building blocks of life: they are the structural subunits of proteins, peptides, and many secondary metabolites. In addition to the 20 α-amino acids that constitute the backbone of proteins, hundreds of other natural α-amino acids have been discovered either ...
Tas Nilufer - - 2010
Many of the hypotheses have been suggested to explain the mechanism of the secondary effects of traumatic spinal cord injury (TSCI) as follows: ischaemia/reperfusion disability theory, free radicals theory, exit otoxicity theory, immunological destruction theory, apoptosis theory. Recently, free radicals,lipid peroxidation reactions and apoptosis theories have been much more accepted ...
Ramaswamy Aishwarya V - - 2010
Lipoic acid is an essential protein bound cofactor that is vital for the functioning of several important enzymes involved in central metabolism. Genomes of all sequenced chlamydiae show the presence of two genes encoding lipoic acid ligases and one gene encoding a lipoate synthase. However, the roles of these proteins ...
Feng Yakai - - 2010
Polydepsipeptides - alternating copolymers of an alpha-amino acid and an alpha-hydroxy acid - are a group of biodegradable polymers. Versatile polydepsipeptides with or without pendant functional groups, as well as various polymer architectures, for example, providing alternative, random, diblock, triblock, multiblock or graft sequence structures, can be synthesized via ring-opening ...
Zhang Jianmin - - 2010
Aluminum-based Lewis acids are effective promoters of the condensation of alpha-chloroglycinates with isonitriles or with cyanide ion, leading to the formation of 5-amino-oxazoles.
Fan Xiang X Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, - - 2010
The regulation and function of lysosomal hydrolases during yolk consumption and embryogenesis in zebrafish are poorly understood. In an effort to better define the lysosomal biochemistry of this organism, we analyzed the developmental expression, biochemical properties, and function of several glycosidases in zebrafish eggs, embryos, and adult tissues. Our results ...
Kim Chi Hyun - - 2010
Fibrates and WY-14643 are widely used as lipid-lowering drugs via modulation of peroxisome proliferator-activated receptor alpha (PPAR α) for the treatment of a wide range of metabolic disorders. Here, to address the question whether PPAR α agonists can affect the enzymatic activity of 11beta-hydroxysteroid dehydrogenase1 (11β-HSD1), we tested fibrates and ...
Emmez Hakan - - 2010
Radical oxygen species produced after injury counteracts antioxidant activity and frequently causes severe oxidative stress for the tissues. Alpha-lipoic acid is a powerful metabolic antioxidant with immunomodulatory effects which provides neuroprotection. The aim of this study is to investigate the neuroprotective and anti-apoptotic effects of alpha-lipoic acid on spinal cord ...
Muzael Maged - - 2010
The synthesis of (2R,3R,Z)-2-docosyl-3-hydroxytetracont-21-enoic acid, a significant alpha'-mycolic acid of Mycobacterium smegmatis and other mycobacteria is reported.
Mammone T - - 2010
J. Cosmet. Sci., 60, 423-428 (July/August 2009) Synopsis Alpha-hydroxy acids have been used topically to treat skin for both dermatological and cosmetic problems for many years. Though there are many known benefits of the use of alpha-hydroxy acids on skin, there have been recent reports that topical treatments with alpha-hydroxy ...
Spalding Maroya D - - 2010
Lipoic acid [(R)-5-(1,2-dithiolan-3-yl)pentanoic acid] is an enzyme cofactor required for intermediate metabolism in free-living cells. Lipoic acid was discovered nearly 60 years ago and was shown to be covalently attached to proteins in several multicomponent dehydrogenases. Cells can acquire lipoate (the deprotonated charge form of lipoic acid that dominates at ...
Hung Jui-Hsiang JH Department of Biochemistry, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Email: - - 2010
Hepatitis B virus (HBV) infection is highly correlated with hepatocellular carcinoma. Previous studies have reported that expression of hepatitis B virus pre-S2 mutant surface antigen is related to hepatoma development. An aberrant carbohydrate metabolism is a hallmark of malignant transformation. We performed yeast two-hybrid screening with HBV pre-S2-del large surface ...
Wright Karen - - 2010
The novel alpha-amino acid BpAib, a partially conformationally restricted analogue of the currently extensively used 3-(4-benzoylphenyl)alanine (Bpa) photoaffinity label, was synthesized, optically resolved, fully characterized, and appropriately derivatized. An intermolecular photocrosslinking experiment highlighted its regioselective reactivity towards the S-methyl side-chain group of a Met-based dipeptide, which is closely comparable to ...
Alba Andrea-Nekane R - - 2010
A new, easy, and highly enantioselective method for the synthesis of quaternary alpha-alkyl-alpha-amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1-bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords alpha,alpha-disubstituted alpha-amino acid derivatives with complete C4 regioselectivity and with excellent yields and ...
Cagini Carlo - - 2010
PURPOSE: To determine the concentration of alpha-lipoic acid in the aqueous and investigate if its topical instillation can increase quantities. METHODS: A total of 70 patients selected to undergo cataract surgery were randomly divided into two groups. Group 1 was used as a control group; for the patients in Group ...
Intelmann Daniel - - 2010
The iso-alpha-acids, the major contributor to bitter beer taste, is well-known to strongly degrade during beer aging. The storage of beer in brown glass bottles revealed a strong depletion of the trans-configured isomers in a highly specific manner, whereas the corresponding cis-iso-alpha-acids seemed to be hardly affected. In comparison, storage ...
Ruby Maxwell A - - 2010
Recent evidence suggests that lipoproteins serve as circulating reservoirs of peroxisomal proliferator activated receptor (PPAR) ligands that are accessible through lipolysis. The present study was conducted to determine the biochemical basis of PPAR-alpha activation by lipolysis products and their contribution to PPAR-alpha function in vivo. PPAR-alpha activation was measured in ...
Paul Souren - - 2010
Microbial conversion of unsaturated fatty acids often leads to special changes in their product structures and in biological potential. In our continuous effort to screen natural products for their antimicrobial and enzyme inhibitor activities, we found that 10-hydroxy-8(E)-octadecenoic acid (HOD) exhibited strong anti-alpha-glucosidase (EC 3.2.1.20) activity. HOD is an intermediate ...
Hassan Malekinejad - - 2010
Zearalenone (ZEA) as a mycoestrogen is found frequently in human foods and animal feeds. Its estrogenic effects depend on its biotransformation fate including both first- and second-phase reactions, which are predominantly governed by hydroxylation and glucuronidation, respectively. In this study, we investigate the hepatic biotransformation of ZEA in river buffalo. ...
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 Y Chemistry Department, Oakland University, Rochester, Michigan 48309, - - 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 S Department of Chemistry, Georgia State University, Atlanta, GA 30302-4098, - - 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.
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