Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sugar Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2000

Synthesis and conformational studies of peptidomimetics containing furanoid sugar amino acids and a sugar diacid.

Furanoid sugar amino acids (1) were synthesized and used as dipeptide isosteres to induce interesting turn structures in small linear peptides. They belong to a new variety of designed hybrid structures that carry both amino and carboxyl groups on rigid furanose sugar rings. Four such molecules, 6-amino-2,5-anhydro-6-deoxy-D-gluconic acid (3, Gaa) and its mannonic (4, Maa), idonic (5, Iaa), and a 3,4-dideoxyidonic (6, ddIaa) congeners were synthesized. The synthesis followed a novel reaction path in which an intramolecular 5-exo S(N)2 opening of the hexose-derived terminal aziridine ring in 2 by the gamma-benzyloxy oxygen with concomitant debenzylation occurred during pyridinium dichromate oxidation of the primary delta-hydroxyl group to carboxyl function, leading to the formation of furanoid sugar amino acid frameworks in a single step. Incorporation of these furanoid sugar amino acids into Leu-enkephalin replacing its Gly-Gly portion gave analogues 8-11. Detailed structural analysis of these molecules by circular dichroism (CD) and various NMR techniques in combination with constrained molecular dynamics (MD) simulations revealed that two of these analogues, 8a and 10a, have folded conformations composed of an unusual nine-membered pseudo beta-turn-like structure with a strong intramolecular H-bond between LeuNH --> sugarC3-OH. This, in turn, brings the two aromatic rings of Tyr and Phe in close proximity, a prerequisite for biological activities of opioid peptides. The analgesic activities of 8a,b determined by mouse hot-plate and tail-clip methods were similar to that of Leu-enkephalin methyl ester. The syn disposition of the beta-hydroxycarboxyl motif on the sugar rings appears to be the driving force to nucleate the observed turn structures in some of these molecules (8 and 10). Repetition of the motif on both sides of a furanose ring resulted in a novel molecular design of sugar diacid, 2,5-anhydro-D-idaric acid (7, Idac). Bidirectional elongation of the diacid moieties of 7 with identical peptide strands led to the formation of a C2-symmetric reverse-turn mimetic 12 which displayed a very ordered structure consisting of identical intramolecular H-bonds at two ends between LeuNH --> sugar-OH, the same as in 8 and 10.

Amino Acids↗
PubMed2003

A transfer of carbon atoms from fatty acids to sugars and amino acids in yellow lupine (Lupinus luteus L.) seedlings.

The metabolism of 14C-acetate was investigated during the in vitro germination of yellow lupine seeds. Carbon atoms (14C) from the C-2 position of acetate were incorporated mainly into amino acids: aspartate, glutamate, and glutamine and into sugars: glucose, sucrose, and fructose. In contrast to this, 14C from the C-1 position of acetate was released mainly as 14CO2. Incorporation of 1-14C and 2-14C from acetate into amino acids and sugars in seedling axes was more intense when sucrose was added to the medium. However, in cotyledons where lipids are converted to carbohydrates, this process was inhibited by exogenous sucrose. Since acetate is the product of fatty acid beta-oxidation, our results indicate that, at least in lupine, seed storage lipids can be converted not only to sucrose, but mainly to amino acids. Inhibitory effects of sucrose on the incorporation of 14C from acetate into amino acids and sugars in cotyledons of lupine seedlings may be explained as the effect of regulation of the glyoxylate cycle by sugars.

Acetates↗
PubMed2006

Microbial metabolomics with gas chromatography/mass spectrometry.

An analytical method was set up suitable for the analysis of microbial metabolomes, consisting of an oximation and silylation derivatization reaction and subsequent analysis by gas chromatography coupled to mass spectrometry. Microbial matrixes contain many compounds that potentially interfere with either the derivatization procedure or analysis, such as high concentrations of salts, complex media or buffer components, or extremely high substrate and product concentrations. The developed method was extensively validated using different microorganisms, i.e., Bacillus subtilis, Propionibacterium freudenreichii, and Escherichia coli. Many metabolite classes could be analyzed with the method: alcohols, aldehydes, amino acids, amines, fatty acids, (phospho-) organic acids, sugars, sugar acids, (acyl-) sugar amines, sugar phosphate, purines, pyrimidines, and aromatic compounds. The derivatization reaction proved to be efficient (>50% transferred to derivatized form) and repeatable (relative standard deviations <10%). Linearity for most metabolites was satisfactory with regression coefficients better than 0.996. Quantification limits were 40-500 pg on-column or 0.1-0.7 mmol/g of microbial cells (dry weight). Generally, intrabatch precision (repeatability) and interbatch precision (reproducibility) for the analysis of metabolites in cell extracts was better than 10 and 15%, respectively. Notwithstanding the nontargeted character of the method and complex microbial matrix, analytical performance for most metabolites fit the requirements for target analysis in bioanalysis. The suitability of the method was demonstrated by analysis of E. coli samples harvested at different growth phases.

Bacillus subtilis↗
PubMed1972

Effects of acetate and other short-chain fatty acids on sugar and amino acid uptake of Bacillus subtilis.

Acetate and other short chain n-fatty acids (C(1)-C(6)) inhibit strongly the uptake of l-serine or other l-amino acids but inhibit only weakly that of alpha-methylglucoside or fructose, whether measured in whole cells of Bacillus subtilis or in membrane vesicles that have been energized with reduced nicotinamide adenine dinucleotide (NADH), l-alpha-glycerol phosphate, or ascorbate plus phenazine methosulfate. The acetate inhibition is noncompetitive, as was shown for l-alpha-aminoisobutyric acid uptake by whole cells and for l-serine uptake by membrane vesicles. In membrane preparations, neither NADH oxidation nor the reduction of cytochromes by NADH are affected by fatty acids. All of these effects are similar to those of 2, 4-dinitrophenol. It is concluded that the fatty acids "uncouple" the amino acid carrier proteins from the cytochrome-linked electron transport system (to which they may be coupled via protein interaction or via a cation gradient).

Acetates↗
PubMed1999

Pilot study of gas chromatographic-mass spectrometric screening of newborn urine for inborn errors of metabolism after treatment with urease.

Gas chromatographic-mass spectrometric (GC-MS) techniques for urinary organic acid profiling have been applied to high-risk screening for a wide range of diseases, mainly for inborn errors of metabolism (IEM), rather than to low-risk screening or mass screening. Using a simplified procedure with urease-pretreatment and the GC-MS technique, which allows simultaneous determination of organic acids, amino acids, sugars and sugar acids, we performed a pilot study of the application of this procedure to neonatal urine screening for 22 IEM. Out of 16,246 newborns screened, 11 cases of metabolic disorders were chemically diagnosed: two each of methylmalonic aciduria and glyceroluria, four of cystinuria, and one each of Hartnup disease, citrullinemia and alpha-aminoadipic aciduria/alpha-ketoadipic aciduria. The incidence of IEM was thus one per 1477, which was higher than the one per 3000 obtained in the USA in a study targeting amino acids and acylcarnitines in newborn blood spots by tandem mass spectrometry. Also, 227 cases were found to have transient metabolic abnormalities: 108 cases with neonatal tyrosinuria, 99 cases with neonatal galactosuria, and 20 cases with other transient metabolic disorders. Two hundred and thirty-eight cases out of 16,246 neonates (approximately 1/68) were thus diagnosed using this procedure as having either persistent or transient metabolic abnormalities.

Gas Chromatography-Mass Spectrometry↗
PubMed1966

Ethanolamine metabolism in plant tissues.

Ethanolamine is readily metabolized by oat, pea, wheat, apple and carrot tissue preparations. Ethanolamine-1,2 (14)C was incorporated into the lipid fraction, and (14)C activity was distributed in the organic acid, sugar, acid volatile, carbon dioxide and insoluble residue fractions. The distribution varied with the particular tissue. Incorporation into the lipid fraction occurred in tissue homogenates in the absence of ATP by a Ca(++) activated system similar to that reported for animal preparations. The initial step in ethanolamine oxidation involves an amine oxidase. Glycolaldehyde and glyoxylic acid are metabolic intermediates, the former in the conversion of ethanolamine to carbon dioxide. No evidence was obtained for the operation of an ethanolamine transaminase or for the involvement of phosphorylated intermediates in the conversion of ethanolamine to carbon dioxide.

Amino Alcohols↗
PubMed2003

Modeling of the hydrolysis of sugar cane bagasse with hydrochloric acid.

Sugar cane bagasse was hydrolyzed under different concentrations of hydrochloric acid (2-6%), reaction times (0-300 min), and temperatures (100-128 degrees C). Sugars obtained (xylose, glucose, arabinose, and glucose) and degradation products (furfural and acetic acid) were determined. Based on the Saeman model and the two-fraction model, kinetic parameters for predicting these compounds in the hydrolysates were developed. The influence of temperature was studied using the Arrhenius equation. The optimal conditions selected were 128 degrees C, 2% HCl, and 51.1 min. Using these conditions, 22.6 g xylose/L, 3.31 g arabinose/L, 3.77 g glucose/L, 3.59 g acetic acid/L, and 1.54 g furfural/L were obtained.

Acetic Acid↗
PubMedDate not supplied

The amino acid composition and quantitative sugar-amino acid relationships in sequential Smith-degradation products from gum talha (Acacia seyal Del.).

Data are presented for the amino acid and sugar compositions of gum talha (tahl), i.e. the exudate from Acacia seyal Del., and for four sequential Smith-degradation (SD) products (0.10, 0.19, 0.38, 1.60 and 2.22% N respectively). Gum talha, which is not permitted as a food additive, is liable to occur as a contaminant of shipments of legitimate gum arabic (Acacia senegal (L.) Willd.). The molar polysaccharide/protein ratio in the whole gum (113:1) decreased to 58:1, 27:1, 5.5:1 and 4:1 in the first, second, third and fourth SD products respectively. From previous studies, SD-IV is known to be a branched galactan; hydroxyproline, aspartic acid, serine, valine, proline, and leucine account jointly for 70% of its amino acids. The first SD eliminated large amounts of sugars (ca 50%, including all of the rhamnose and glucuronic acid present) but only very small amounts of amino acids (molar ratio 807/1). The second and third degradations eliminated all of the arabinose and 99% of the galactose originally present. The very small yield of the final SD product is an established characteristic of dextrorotatory Acacia exudates of the A. seyal type (Bentham's Gummiferae). Overall (four SD stages), 99.7% of the original sugars but only 91.3% of the amino acids were eliminated. Hydroxyproline accounts for ca 25% of the low amino acid content of A. seyal gum and each of its SD products; the proteinaceous enrichment of the branched galactan core also involves aspartic acid, glutamic acid and iso-leucine.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed2005

Biodegradable composites from sugar beet pulp and poly(lactic acid).

Sugar beet pulp and poly(lactic acid) (PLA) composites were prepared by compression-heating. The resultant thermoplastics had a lower density, but they had tensile strength similar to that of pure PLA specimens as well as the same geometric properties. Tensile properties depended on the initial water content of sugar beet pulp and the process by which composites were manufactured. In comparison with sugar beet pulp, the composite showed improved water resistance. This can be attributed to the hydrophobic character of PLA and pulp-matrix interactions. The composite thermoplastics showed suitable properties for potential use as lightweight construction materials.

Beta vulgaris↗
PubMed2006

Changes in organic acids and sugars during early stages of development of acidic and acidless citrus fruit.

Most of the studies on organic acids and sugars in citrus were performed during fruit maturation, and less is known before this stage of development. The aim of our study was to investigate acids and sugars in lemon, lime, and orange from fruit-set toward development. We chose to compare organic acid and sugar accumulation among acidic and acidless varieties within three species. We estimated the acidity by titrimetry and quantified the concentrations of seven organic acids and three sugars by reverse HPLC. During the first 50 days of development, quinic acid was the major organic acid whatever the variety. Afterward, citric acid predominated in acidic varieties, while in acidless, malic acid exceeded it. Fructose substituted citric acid in acidless and could be synthesized either from citric acid or directly from glucose. Our results provided the first complete report on sugar and organic acid accumulation during the early stages of fruit development in several citrus varieties.

Carbohydrates↗
PubMed2004

Acidic oligosaccharide sugar chain, a marine-derived acidic oligosaccharide, inhibits the cytotoxicity and aggregation of amyloid beta protein.

In this paper, we investigated interactions of the acidic oligosaccharide sugar chain (AOSC), derived from brown algae Echlonia kurome OKAM, with amyloid beta protein (Abeta). We observed that AOSC inhibited the toxicity induced by Abeta in both primarily cortical cells and the SH-SY5Y cell line. We also observed that AOSC inhibited the apoptosis induced by Abeta in SH-SY5Y by reducing the elevated level of intracellular calcium concentration ([Ca(2+)](i)) and suppressing the generation of reactive oxygen species. Surface plasmon resonance analysis demonstrated that AOSC had affinity for both freshly-dissolved Abeta and 48-h incubated Abeta. Furthermore, AOSC blocked the fibril formation of Abeta, which may be responsible for its anti-cytotoxic effects. Thus, our results indicate that AOSC might be a potentially therapeutic compound for Alzheimer's disease.

Amyloid beta-Peptides↗