We report second-order rate constants of kDO = 120 dm(3) mol(-1) s(-1) and kB = 6.4 x 10(-4) dm(3) mol(-1) s(-1) for exchange for deuterium of the first alpha-methylene proton of the 4-(aminomethyl)pyridine dication in D2O at 25 degree C and I= 1.0 (KCl). These data are consistent with a ...

We report on a structural (multinuclear NMR), thermodynamic (pK(a)), and kinetic (Marcus intrinsic reactivity) study of the ionization of benzylic carbon acids activated by an exocyclic (alpha) SO(2)CF(3) group and SO(2)CF(3) or S(O)(=NSO(2)CF(3))CF(3) in the para position of the phenyl ring. The latter exerts an enormous acidifying effect of ca. ...

Substituted 3-amino-oxazolidin-2,4-diones have been prepared by reacting cyanohydrins or alpha-hydroxyesters subsequently with 1,1'-carbonyldiimidazole and 1,1-disubstituted hydrazines followed by acidic hydrolysis in case of the intermediate 3-amino-4-imino-oxazolidin-2-ones. Conventional and microwave-assisted syntheses of N',N'-disubstituted alpha-hydroxyhydrazides have been accomplished by reacting substituted 3-amino-oxazolidin-2,4-diones with catalytic amounts of sodium methoxide in methanol.

Use of partial or selective (13)C/(15)N labeling of specific amino acid residues in a given protein to measure the values of (1)J((15)N(i),(13)C(alpha) (i)), (2)J((1)H(N),(13)C(alpha) (i)), (2)J((15)N(i),(13)C(alpha) (i-1)), (1)J((15)N(i),(13)C'(i-1)) and (2)J((1)H(N),(13)C'(i-1)) is described. This was achieved by recording a sensitivity-enhanced 2D [(15)N-(1)H] HSQC experiment, without mixing the spin states of C(alpha) ...

OBJECTIVE: To determine whether key appetite-regulating neuropeptides such as melanin-concentrating hormone (MCH), neuropeptide Y (NPY), and alpha-melanocyte-stimulating hormone (alpha-MSH), which are known to mediate energy balance through centrally mediated pathways, also have direct acute effects on the lipolytic activity of murine adipocytes. RESEARCH METHODS AND PROCEDURES: Fully differentiated 3T3-L1 adipocytes ...

Interferon-alpha (IFN-alpha) therapy is strongly associated with certain adverse effects, but the pathophysiologic mechanism is unclear. The present study was designed to investigate the influence of peripherally administered IFN- alpha on amino acid levels in the brain. IFN-alpha was administered intraperitoneally (i.p.) once daily to rats, and their brains were ...

Binucleate Rhizoctonia (BNR) isolate (232-C6) is an effective biocontrol agent for protection of potato from Rhizoctonia canker, a disease caused by Rhizoctonia solani. Production of hydrolytic enzymes is one of the best known inducible defense responses following microbial infection. We isolated and characterized a cell wall alpha-glucan from BNR, which ...

As a continuation of our SAR studies of dipeptidyl aspartyl-fmk as caspase inhibitors, we explored the replacement of the P2 alpha-amino acid by a peptidomimetic alpha-hydroxy acid. These alpha-carbamoyl-alkylcarbonyl-aspartyl fluoromethylketones were found to be potent caspase inhibitors, and the SAR of these compounds is similar to the corresponding dipeptidyl aspartyl-fmk. ...

A new alpha-glucuronidase that specifically hydrolyzed O-alpha-D-glucosyluronic acid alpha-D-glucosiduronic acid (trehalose dicarboxylate, TreDC) was purified from a commercial enzyme preparation from Aspergillus niger, and its properties were examined. The enzyme did not degrade O-alpha-D-glucosyluronic acid alpha-D-glucoside, O-alpha-D-glucosyluronic acid beta-D-glucosiduronic acid, O-alpha-D-glucosyluronic acid-(1-->2)-beta-D-fructosiduronic acid, p-nitrophenyl-O-alpha-D-glucosiduronic acid, methyl-O-alpha-D-glucosiduronic acid, or 6-O-alpha-(4-O-alpha-D-glucosyluronic acid)-D-glucosyl-beta-cyclodextrine. ...

In an open-label, parallel-group study involving 16 patients (8 with severely reduced renal function, 8 with end-stage renal disease needing hemodialysis), the effect of renal function on the pharmacokinetics, metabolism, and safety and of alpha-lipoic acid (thioctic acid) was evaluated by comparing the pharmacokinetic parameters with those of a reference ...

Ceramide mono (CMH) or dihexoside (CDH) fractions from Trypanosoma cruzi (Dm28c clone) were identified as glucosyl and lactosylceramides containing non-hydroxylated fatty acids. The di-glycosylated form was much more efficiently recognized by sera from T. cruzi-immunized rabbits, indicating that glycosylation influences antigenicity. Fatty acid hydroxylation was also a determinant of serological ...

Raman spectroscopy (RS) was used to determine the crystallinity of lactose (a commonly used carrier in dry powder inhaler (DPI) formulations). Samples of alpha-lactose monohydrate and amorphous lactose were prepared using ethanol precipitation and lyophilisation respectively. The anomeric forms were confirmed using DSC at a rate of 10 degrees C/min ...

BACKGROUND: The metabolic syndrome is associated with increased angiotensin II activity, induction of a proinflammatory and oxidative state, and endothelial dysfunction. We evaluated the ability of irbesartan, an angiotensin receptor blocker, and lipoic acid, an antioxidant, to affect endothelial function and inflammation in patients with the metabolic syndrome. METHODS AND ...

Peptide ribonucleic acid (PRNA) is one of artificial nucleic acids, which enables us to control its nucleobase orientation and recognition behavior by external factors through the synergetic effects of reversible borate ester formation and intramolecular hydrogen bond formation. In this study, a series of novel alpha-PRNA oligomers, possessing alternative alpha-PRNA/basic ...

PURPOSE: The purpose of this study was to determine the protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation. METHODS: 20 rabbits weighing 2,500- 3,000 g were used, and we divided them into 4 groups with 5 randomly selected rabbits. The rabbits ...

The role of the periplasmic alpha-carbonic anhydrase (alpha-CA) (HP1186) in acid acclimation of Helicobacter pylori was investigated. Urease and urea influx through UreI have been shown to be essential for gastric colonization and for acid survival in vitro. Intrabacterial urease generation of NH3 has a major role in regulation of ...

FA with varying chain lengths and an alpha-methyl group and/or a sulfur in the beta-position were tested as peroxisome proliferator-activated receptor (PPAR)alpha, -delta(beta), and -gamma ligands by transient transfection in COS-1 cells using chimeric receptor expression plasmids, containing cDNAs encoding the ligand-binding domain of PPARalpha, -delta, and -gamma. For PPARalpha, ...

We have examined the effects of midazolam, Ro 5-4864 (agonist for "peripheral" [p] benzodiazepine receptors [BR]), PK 11195 (antagonist for pBR), flumazenil (antagonist for "central" BR), naloxone (antagonist for opiate receptors) and the combination of midazolam and Ro 5-4864, PK 11195, flumazenil or naloxone on intracellular amino- and alpha-keto acids ...

A simple method for preparation of fluoroalkyl beta-enaminophosphonates 1 from alkylphosphonates 2 and perfluoroalkyl nitriles 3 is reported. Olefination reaction of functionalized phosphates 1 with aldehydes gives alpha,beta-unsaturated imines 5. Acid hydrolysis of these fluoroalkyl derivatives 5 affords alpha,beta-unsaturated ketones 6, while their selective reduction with hydrides leads to the ...

The physiological effects of 9cis,11trans,13cis-conjugated linolenic acid (9c,11t,13c-CLNA), one of the CLNA isomers, were studied in human hepatoma HepG2 cells. 9c,11t,13c-CLNA significantly decreased apolipoprotein B100 secretion compared with alpha-linolenic acid (alpha-LNA). The uptake of (14)C-oleate into newly synthesized cellular triacylglycerol was also decreased by 9c,11t,13c-CLNA more than by alpha-LNA treatment. ...

Non-alpha-tocopherols are hydroxymethylated and hydrogenated to produce alpha-tocopherol in one pot process by simultaneously reacting with paraformaldehyde and hydrogen in the presence of catalysts of benzenesulfonic acid and 5% Pd/C in an autoclave. Effects of various operation conditions have been studied. The preferable reaction conditions are: temperature 180 degrees C ...

Obesity shortens life expectancy and is a risk factor for hypertension and Type 2 diabetes. When added to the standard chow of Sprague-Dawley or Otsuka Long-Evans Tokushima Fatty rats, alpha-lipoic acid (0.5% weight/weight) reduced body weight and food intake. Alpha-lipoic acid also increased whole-body energy expenditure. It exerts its effects ...

A series of zwitterionic lambda(5)Si-silicates with a (2,2,6,6-tetramethylpiperidinio)methyl group and two identical bidentate ligands derived from glycine, (S)-alanine, (S)-phenylalanine, glycolic acid, (S)-lactic acid, (S)-3-phenyllactic acid, or (S)-mandelic acid were synthesized and structurally characterized (solution and solid-state NMR spectroscopy; single-crystal X-ray diffraction). The chiral lambda(5)Si-silicates with ligands derived from optically active ...

We examined the mechanisms underlying the activation of group IVA cytosolic phospholipase A(2) (cPLA(2)alpha) contributing to the supply of fatty acids required for the formation of cholesteryl ester in oxidized low-density lipoprotein (oxLDL)-stimulated macrophages. The possible involvement of oxidized lipids was also examined. In [(3)H]arachidonic acid-labeled mouse peritoneal macrophages, oxLDL ...

The objective of this study was to determine the effects of ornithine on polymorphonuclear leucocyte (PMN) free amino- and alpha-keto acid profiles, superoxide anion (O2-) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase activity (MPO). Exogenous ornithine significantly increased PMN asparagine, glutamine, aspartate, glutamate, arginine, citrulline, alanine, alpha-ketoglutarate and pyruvate ...

o-Phthalaldehyde in combination with chiral thiols is described as a chiral reagent for the resolution of the enantiomers of alpha-H-alpha-aminonitriles and alpha-alkyl-alpha-aminonitriles. Separation of the resulting diastereomers was carried out by reversed-phase chromatography and the derivatives were detected at UV 340 nm. The identity of the diastereomeric derivatives was confirmed ...

Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and alpha-keto acids is one mechanism to generate these flavorful ...

OBJECTIVE: We have examined the effect of alpha-lipoic acid (ALA, tioctic acid; Tiobec), a free radical scavenger, on the discomfort of burning mouth syndrome (BMS) in patients who had used tranquillizers previously, compared with those who had not. METHODS: In this study we gave lipoic acid for 2 months to ...

Dissolution enthalpies of L-alpha-aminobutyric acid, L-alpha-isoleucine, L-alpha-phenylalanine, L-alpha-methionine, L-alpha-serine, L-alpha-threonine, L-alpha-cysteine, L-alpha-asparagine and L-alpha-glutamine in aqueous solutions of urea have been measured by calorimetry at 298.15 K. The obtained results were used to calculate the enthalpic interaction coefficients between the zwitterions of the L-alpha-amino acids and a molecule of urea ...

Lipoic acid was found to inhibit the firefly luciferin-luciferase reaction. The inhibition is competitive and is the strongest known (Ki = 0.026 +/- 0.013 microM) compared with other reported inhibitors. Considering the structure-activity correlations, the mechanism of inhibition may originate from the sulfur atom and carboxyl moiety of lipoic acid ...

[reaction: see text] We report a new enantioselective synthesis of (-)-alpha-kainic acid from d-serine methyl ester hydrochloride, based on a (-)-sparteine-mediated asymmetric deprotonation of an intermediate carbamate that, by stereospecific anti S(N)'S(E)' intramolecular cycloalkylation, leads to the pyrrolidine ring precursor of (-)-alpha-kainic acid, in high yield and diastereoselectivity. The intermediate ...

A practical, one-pot process for the preparation of beta-keto amides via a three-component reaction, including Meldrum's acid, an amine, and a carboxylic acid, has been developed. Key to development of an efficient, high-yielding process was an in-depth understanding of the mechanism of the multistep process. Kinetic studies were carried out ...

The four pyruvate dehydrogenase kinase (PDK) and two pyruvate dehydrogenase phosphatase (PDP) isoenzymes that are present in mammalian tissues regulate activity of the pyruvate dehydrogenase complex (PDC) by phosphorylation/dephosphorylation of its pyruvate dehydrogenase (E1) component. The effect of lipoic acids on the activity of PDKs and PDPs was investigated in ...

External addition of the beta-lactam precursor alpha-aminoadipic acid to the filamentous fungus Penicillium chrysogenum leads to an increased intracellular alpha-aminoadipic acid concentration and an increase in penicillin production. The exact route for alpha-aminoadipic acid uptake is not known, although the general amino acid and acidic amino acid permeases have been ...

The gas-phase acidity of D-glucopyranose was studied by means of B3LYP calculations combined with 6-31G(d,p) or 6-31+G(d,p) standard basis sets. For each anomer, deprotonation of the various primary and secondary hydroxyl groups was considered. As in solution, the anomeric hydroxyl is found to be the most acidic for both anomers, ...

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20) catalysed hydrogen-deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine at pH 7.8. 1H-NMR has also been used to follow the tryptophan-synthase-catalysed hydrogen-deuterium exchange of the alpha-protons of a range of L- and D-amino acids at pH 7.8. ...

Metabolism of aromatic amino acids by lactic acid bacteria is an important source of off-flavor compounds in Cheddar cheese. Previous work has shown that alpha-keto acids produced from Trp, Tyr, and Phe by aminotransferase enzymes are chemically labile and may degrade spontaneously into a variety of off-flavor compounds. However, dairy ...

Lipoic acid is an essential cofactor of alpha-keto acid dehydrogenase complexes (KADHCs). This study shows that Plasmodium falciparum possesses two distinct lipoylation pathways that are found in separate subcellular localizations. Lipoic acid synthesis comprising lipoic acid synthase and lipoyl-ACP:protein N-lipoyl transferase is present in the parasite's apicoplast, whereas the second ...

Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus ...

Detailed investigation on the origin of the acidity of the alpha-protons of a set of the carbonyl molecules was carried out on the basis of properties of the localized molecular orbital. An anomalously high acidity of Meldrum's acid, as compared with those of dimedone and dimethyl malonate, is one of ...

BACKGROUND: We studied the effect on skin papillomas of topical application of a complex of alpha-lactalbumin and oleic acid (often referred to as human alpha-lactalbumin made lethal to tumor cells [HAMLET]) to establish proof of the principle that alpha-lactalbumin-oleic acid kills transformed cells but not healthy, differentiated cells. METHODS: Forty ...

O-Protected 3-hydroxyoxazolidin-2,4-diones have been prepared in a novel one-pot reaction by subsequent treatment of cyanohydrins with 1,1'-carbonyldiimidazole and O-protected hydroxylamines followed by acidic hydrolysis of the intermediate 4-imino-oxazolidin-2-ones. Decarbonylation of O-protected 3-hydroxyoxazolidin-2,4-diones by catalytic amounts of sodium methoxide, lithium hydroxide, sodium carbonate and caesium carbonate in methanol afforded O-protected alpha-hydroxyhydroxamic ...

trans-Cinnamic acid and its derivatives were investigated for the alpha-glucosidase inhibitory activity. 4-Methoxy-trans-cinnamic acid and 4-methoxy-trans-cinnamic acid ethyl ester showed the highest potent inhibitory activity among those of trans-cinnamic acid derivatives. The presence of substituents at 4-position in trans-cinnamic acid altered the alpha-glucosidase inhibitory activity. Increasing of bulkiness and the ...

A stereoselective synthesis of functionalised (2R,3R)-2,3-dimethyl-3-amidotetrahydrofuran-4-one, its (2S,3R)-epimer and (3aR,6aR)-N-(3-oxo-hexahydrocyclopenta[b]furan-3a-yl)acylamide cysteinyl proteinase inhibitors has been developed using Fmoc-protected scaffolds 6-8 in a solid-phase combinatorial strategy. Within these scaffolds, the introduction of an alkyl substituent alpha to the ketone affords chiral stability to an otherwise configurationally labile molecule. Preparation of scaffolds ...

A chelating resin was synthesized by incorporating thiosemicarbazide into Amberlite IRC-50, a weakly acidic polymer. Astatine radionuclides produced by alpha-irradiating bismuth oxide were separated using the newly synthesized chelating resin. The resin showed high selectivity for astatine. The adsorbed astatine was recovered using 0.1M EDTA at pH approximately 10.

Camphene is an industrial intermediate compound for commercial chemicals such as isoborneol, isobornyl acetate and camphor. Industrially, the conventional process for camphene production consists of the isomerization of alpha-pinene using acidic TiO2 as catalyst. The use of this catalyst presents problems such as considerable time for preparation, reproducibility and recovery ...

Five-, six-, and seven-membered cyclic alpha-amino phosphonates, amino acid surrogates, are prepared in enantiomerically pure form via the highly diastereomeric addition of metal phosphonates to masked oxo sulfinimines. Hydrolysis of the resulting masked oxo alpha-amino phosphonates followed by reduction of the intermediate cyclic imino phosphonates affords the title compounds in ...

Protected alpha-formyl amino acids, themselves available from the corresponding alpha-vinyl amino acids, are stereoselectively transformed into the (Z)-configured alpha-(2'-fluoro)vinyl amino acids via a three-step sequence. The route employs McCarthy's reagent, diethyl alpha-fluoro-alpha-(phenylsulfonyl)methyl phosphonate, and proceeds via the intermediate (E)-alpha-fluorovinyl sulfones and (E)-alpha-fluorovinylstannanes. The latter may either be exploited as novel ...

alpha-Amino acids are important building blocks for the synthesis of a large number of bioactive compounds and pharmaceutical drugs. However, a literature survey revealed that no theoretical conformational study of alpha-amino acids with cage carbon frameworks has been performed to date. This paper reports the results of a conformational study ...

The interferon-alpha genes from three chicken lines were cloned by a direct PCR technique, and the effects of recombinant protein expressed in a prokaryotic system on highly pathogenic H9N2 influenza viruses were investigated. The cloned ChIFN-alpha gene encoded a protein of 193 amino acids with a signal sequence of 31 ...