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Containing D (containing + d)
Selected AbstractsA Chemoenzymatic Approach for the Synthesis of Unnatural Disaccharides Containing D -Galacto- or D -FucofuranosidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2005Ronan Euzen Abstract Unusual diglycosides composed of D -hexofuranosyl entities were prepared by a chemoenzymatic route using the ,- L -arabinofuranosidase, AbfD3. The required, unprotected monosaccharidic donors were first prepared according to multi-step syntheses. Since one goal of this study was the investigation of donor ,1 subsite in the active site of the enzyme, we focused on D -fucofuranosyl and 6-deoxy-6-fluoro- D -galactofuranosyl derivatives which present stereochemical similarities with L -arabinose series, but also structural variations on the side arm. These substrates were then used in AbfD3-catalysed hydrolyses to determine the parameters Km and kcat and in AbfD3-catalysed transglycosylation to evaluate their ability to serve as donor/acceptor. Four disaccharides were thus isolated and characterised, two resulting from ,-(1,2) connection along with two ,-(1,3)-regioisomers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Highly Potent and Selective Substrate Analogue Factor Xa Inhibitors Containing D -Homophenylalanine Analogues as P3 Residue: Part 2CHEMMEDCHEM, Issue 7 2007Anne Stürzebecher Dr. Abstract A series of highly potent substrate-analogue factor Xa inhibitors containing D -homophenylalanine analogues as the P3 residue has been identified by systematic optimization of a previously described inhibitor structure. An initial lead, benzylsulfonyl- d- hPhe-Gly-4-amidinobenzylamide (3), inhibits fXa with an inhibition constant of 6.0,nM. Most modifications of the P2 amino acid and P4 benzylsulfonyl group did not improve the affinity and selectivity of the compounds as fXa inhibitors. In contrast, further variation at the P3 position led to inhibitors with significantly enhanced potency and selectivity. Inhibitor 27, benzylsulfonyl- D -homo-2-pyridylalanyl(N-oxide)-Gly-4-amidinobenzylamide, inhibits fXa with a Ki value of 0.32,nM. The inhibitor has strong anticoagulant activity in plasma and doubles the activated partial thromboplastin time and prothrombin time at concentrations of 280,nM and 170,nM, respectively. Compound 27 inhibits the prothrombinase complex with an IC50 value of 5,nM and is approximately 50 times more potent than the reference inhibitor DX-9065a in this assay. [source] Discrimination between pentose oligosaccharides containing D -xylopyranose or L -arabinofuranose as non-reducing terminal residue using fast atom bombardment mass spectrometry,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2001Vladimír Ková Abstract Collisional-induced dissociation (CID) mass spectra of the [M + H]+ and [M , H], ions obtained under fast atom bombardment conditions of a number of methyl glycoside di-, tri- and tetrasaccharides, containing D -xylopyranosyl and/or L -arabinofuranosyl residues at the non-reducing terminus, do not provide information about their ring size. This information could only be obtained from a careful comparison of the intensity ratio of the [M + Na , 90]+ and [M + Na , 104]+ ions (0,2Xt/1,5Xt) in the high-energy CID spectra of the sodium-cationized di-, tri- and probably also tetrasaccharide compounds. Copyright © 2001 John Wiley & Sons, Ltd. [source] Endomorphin analogues containing D -Pro2 discriminate different ,-opioid receptor mediated antinociception in miceBRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2002Shinobu Sakurada The antagonistic actions of D -Pro2 -endomorphins on inhibition of the paw withdrawal response by endomorphins were studied in mice. D -Pro2 -endomorphin-1 and D -Pro2 -endomorphin-2, injected intrathecally (i.t.), had no significant effect on the nociceptive thermal threshold alone. When D -Pro2 -endomorphin-1 (0.05,0.1 pmol) was injected simultaneously with i.t. endomorphin-1 (5.0 nmol) or endomorphin-2 (5.0 nmol), antinociception induced by endomoprhin-1 was reduced significantly, whereas endomorphin-2-induced antinociception was not affected by D -Pro2 -endomorphin-1. Antinociception induced by i.t. endomorphin-2 (5.0 nmol) was reduced significantly by its analogue, D -Pro2 -endomorphin-2 (100 pmol), but not by D -Pro2 -endomorphin-1. D -Pro2 -endomorphin-1. D -Pro2 -endomorphin-1 also antagonized the antinociceptive effect of i.t. DAMGO, a ,-opioid receptor agonist, whereas D -Pro2 -endomorphin-2 failed to reduce the effect of DAMGO. These results suggest that endomorphin analogues containing D -Pro2 are able to discriminate the antinociceptive actions of ,1 - and ,2 -opioid receptor agonists at the spinal cord level. British Journal of Pharmacology (2002) 137, 1143,1146. doi:10.1038/sj.bjp.0705047 [source] Highly Potent and Selective Substrate Analogue Factor Xa Inhibitors Containing D -Homophenylalanine Analogues as P3 Residue: Part 2CHEMMEDCHEM, Issue 7 2007Anne Stürzebecher Dr. Abstract A series of highly potent substrate-analogue factor Xa inhibitors containing D -homophenylalanine analogues as the P3 residue has been identified by systematic optimization of a previously described inhibitor structure. An initial lead, benzylsulfonyl- d- hPhe-Gly-4-amidinobenzylamide (3), inhibits fXa with an inhibition constant of 6.0,nM. Most modifications of the P2 amino acid and P4 benzylsulfonyl group did not improve the affinity and selectivity of the compounds as fXa inhibitors. In contrast, further variation at the P3 position led to inhibitors with significantly enhanced potency and selectivity. Inhibitor 27, benzylsulfonyl- D -homo-2-pyridylalanyl(N-oxide)-Gly-4-amidinobenzylamide, inhibits fXa with a Ki value of 0.32,nM. The inhibitor has strong anticoagulant activity in plasma and doubles the activated partial thromboplastin time and prothrombin time at concentrations of 280,nM and 170,nM, respectively. Compound 27 inhibits the prothrombinase complex with an IC50 value of 5,nM and is approximately 50 times more potent than the reference inhibitor DX-9065a in this assay. [source] Physico-chemical studies on a wide composition range of low-moisture glucose,fructose mixtures: rates of crystallisationINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2009Ioannis S. Arvanitoyannis Summary The crystallisation rates of low-moisture (from 2% to 10% w/w) glucose,fructose mixtures were investigated at a variety of storage temperatures (from 0 to 60 °C). It was found that d -fructose considerably retards the rate of crystallisation. High storage temperatures induced a decrease in the ,threshold' moisture content, which is necessary for the initial nucleation and further development of the glucose and/or fructose crystals. This knowledge of crystallisation rates can be exploited in terms of storage of confectionery products containing d -glucose, d -fructose or both of them, and honey. [source] Identification of an essential gene responsible for d -Asp incorporation in the Lactococcus lactis peptidoglycan crossbridgeMOLECULAR MICROBIOLOGY, Issue 6 2006Patrick Veiga Summary Bacteria such as Lactococcus lactis have d -aspartate (d -Asp) or its amidated derivative d -asparagine (d -Asn), in their peptidoglycan (PG) interpeptide crossbridge. We performed a subtractive genome analysis to identify L. lactis gene yxbA, orthologues of which being present only in bacteria containing d -amino acids in their PG crossbridge, but absent from those that instead insert l -amino acids or glycine. Inactivation of yxbA required a complementing Streptococcus pneumoniae murMN genes, which express enzymes that incorporate l -Ser- l -Ala or l -Ala- l -Ala in the PG crossbridge. Our results show that (i) yxbA encodes d -Asp ligase responsible for incorporation of d -Asp in the PG crossbridge, and we therefore renamed it as aslA, (ii) it is an essential gene, which makes its product a potential target for specific antimicrobials, (iii) the absence of d -Asp may be complemented by l -Ser- l -Ala or l -Ala- l -Ala in the L. lactis PG, indicating that the PG synthesis machinery is not selective for the side-chain residues, and (iv) lactococcal strains having l -amino acids in their PG crossbridge display defects in cell wall integrity, but are able to efficiently anchor cell wall proteins, indicating relative flexibility of lactococcal transpeptidation reactions with respect to changes in PG side-chain composition. [source] | ||||||||||