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Relationships between Isomerised Cycloadduct and Epimers Relationships between the Cycloadduct, it's isomer, the epimeric Dihydroxytriones and the Ethynylcarbinols The schemes below illustrate the relationships of the epimeric ketones and ethynlycarbinols formed in the sequences. The end result, expectedly is that the same anthracycline (15) will be formed as the epimeric hydrogens at C-10a (as well as C-6a) are removed by lead tetra-acetate in the oxidation. www.jonathanpmiller.com /epimers   (186 words)

HIV Databases Review Article 1995 The EpiMer algorithm predicted putative T cell epitopes from protein sequences for HIV-1 nef, gp160, gag p55, and tat that required fewer peptides and therefore fewer amino acid residues to be synthesized than either AMPHI-predicted peptides or overlapping peptides. An additional application of EpiMer might be to evaluate the effect of pressure from the immune system of the individual on the HIV quasi-species of that individual. The EpiMer peptides are shown in bold, and are slightly shorter than the stated predictions because the midpoint of the amino terminal 11-mer reading frame of the predicted peptide to the midpoint of the carboxy terminal 11-mer reading frame are designated in this picture, rather than the full length of the predicted peptide. www.hiv.lanl.gov /content/hiv-db/REVIEWS/articles/DeGroot.html   (4445 words)

[No title] The utility of computer-algorithm driven predictions for in vitro and in vivo research was recently demonstrated in an analysis of peptides predicted by the EpiMer algorithm from Mycobacterium tuberculosis (Mtb) protein sequences. The EpiMer algorithm predicted putative T cell epitopes from protein sequences for HIV-1 nef, gp160, gag p55, and tat that required fewer peptides and therefore fewer amino acid residues to be synthesized than either AMPHI-predicted peptides or overlapping peptides. The EpiMer peptides are shown in bold, and are slightly shorter than the stated predictions because the midpoint of the amino terminal 11-mer reading frame of the predicted peptide to the midpoint of the carboxy terminal 11-mer reading frame are designated in this picture, rather than the full length of the predicted peptide. hiv-web.lanl.gov /content/hiv-db/REVIEWS/articles/DeGroot.html   (4378 words)

Epimer - Wikipedia, the free encyclopedia In chemistry, an epimer is a stereoisomer of another compound that has a different configuration at only one of several chiral carbon centers. When an epimer becomes incorporated into a ring structure it is called an anomer. For example, the sugars α-glucose and β-glucose are epimers. en.wikipedia.org /wiki/Epimer   (132 words)

Epimer interconversion, isomerization, and hydrolysis of tetrahydrouridine: Implications for cytidine deaminase ... Epimer interconversion, isomerization, and hydrolysis of tetrahydrouridine: Implications for cytidine deaminase inhibition The aims of this study were to investigate the interconversion kinetics of the epimers of THU, the CDA inhibitory effects of these epimers, and the stability and degradation mechanisms of THU epimer mixtures in aqueous solution with the ultimate goal of developing optimal conditions for a parenteral formulation of THU. Studies at elevated temperature suggested that THU degradation from epimer mixtures is biphasic with the initial rate of disappearance being acid catalyzed and first order in initial THU concentration, thus ruling out dimerization as a potential reaction mechanism. www.aapspharmaceutica.com /search/view.asp?ID=49531   (444 words)

BET2 Software - The identification of epimer alcohols This type of epimers is found in carbohydrates too. The heat of formation by molecule (ΔH) of cations resulted through fragmentation of two epimer alcohols, colons 6 and 7, were calculated by a Computational Quantum Chemistry method. Generally, mass spectrometry alone is unable to establish the chemical epimer structures. www.bet2-soft.de /applications/app1.htm   (462 words)

Stereoselective Disposition of Sulbenicillin in Humans -- Itoh et al. 42 (2): 325 -- Antimicrobial Agents and ... An HPLC was used to determine the concentrations of SBPC epimers. SBPC was incubated with human plasma at 37°C, and the concentrations of the epimers were measured at appropriate times. Epimerization and racemization of some chiral drugs in the presence of human serum albumin. aac.asm.org /cgi/content/full/42/2/325   (3970 words)

Entrez-PubMed To evaluate the predictive power of EpiMer, the amino acid sequences of the HIV-1 proteins nef, gp160, gag p55, and tat were searched for regions of MHC-binding motif clustering. The EpiMer method of T cell epitope identification was compared to the standard method of synthesizing short, overlapping peptides and testing them for immunogenicity (overlapping peptide method), and to an alternate algorithm that has been used to identify putative T cell epitopes from primary structure (AMPHI). For the four HIV-1 proteins analyzed, the in vitro testing of EpiMer peptides for immunogenicity would have required the synthesis of fewer total peptides than either AMPHI or the overlapping peptide method. www.cbrinstitute.org /labs/lieberman/pdf/1996RobertsA.htm   (286 words)

epimer - OneLook Dictionary Search We found 9 dictionaries with English definitions that include the word epimer: Tip: Click on the first link on a line below to go directly to a page where "epimer" is defined. Epimer : Drug Discovery and Development [home, info] www.onelook.com /?w=epimer   (111 words)

EPA: Federal Register: Lambda-cyhalothrin; Time-Limited Pesticide Tolerance The names for lambda-cyhalothrin and its epimer are as follows: Lambda- cyhalothrin, a 1:1 mixture of (S)-alpha-cyano-3-phenoxybenzyl-(Z)- (1R,3R)-3-(2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2- dimethylcyclopropanecarboxylate and (R)-alpha-cyano-3-phenoxybenzyl- (Z)-(1S,3S) -3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2- dimethylcyclopropanecarboxylate and Epimer of lambda-cyhalothrin, a 1:1 mixture of (S)-alpha-cyano-3-phenoxybenzyl-(Z)-(1S,3S)-3-(2-chloro- 3,3,3- trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate and (R)-alpha-cyano-3-phenoxybenzyl-(Z)-(1R,3R)-3-(2-chloro-3,3,3- trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate. The residues to be regulated are lambda-cyhalothrin and its epimer as specified in 40 CFR 180.438. Conclusion A time limited tolerance is being established for lambda- cyhalothrin and its epimer, in/or on rice grain at 1.0 ppm, rice straw at 1.8 ppm, and rice hulls at 5.0 ppm. www.epa.gov /fedrgstr/EPA-PEST/1997/July/Day-09/p17591.htm   (5591 words)

✓ Epimer - Antiagingdiät.de - Antiagingdiät Als Epimere bezeichnet man Paare von Diastereoisomeren eines Moleküls mit mehreren Chiralitätszentren, die sich nur an einem dieser Zentren unterscheiden (z.B. Isoleucin und Alloisoleucin (siehe Grafik rechts) oder auch Glucose und Galactose). Epimere sind somit immer auch Diastereomere, aber nicht umgekehrt. In der Zuckerchemie benutzt man den Begriff Anomer als Spezialfall eines Epimers, dessen Unterschied am ersten Kohlenstoff liegt (relevant bei Bildung der α- oder β-Form eines Zuckers wie der Glucose). xn--antiagingdit-qcb.de /index.php/Epimer   (1863 words)

Carbohydrates   (Site not responding. Last check: 2007-10-17) Glucose and mannose are therefore epimers at C-2, a fact confirmed by the common product from their osazone reactions. In order to determine which of these epimers was glucose, Fischer made use of the inherent C Because of this symmetry, if the aldehyde and 1º-alcohol functions at the ends of the chain are exchanged, epimer B would be unchanged; whereas A would be converted to a different compound. www.cem.msu.edu /~reusch/VirtualText/carbhyd.htm   (4755 words)

Anthracycline chemistry It should be noted that some epimerisation at the ring junction occurs; this is not a problem as lead tetra-acetate oxidation removes these hydrogen atoms, to give the red aromatic compound (15). Exp.17 - Ethynylation and oxidation of the 10a-H epimer of ketone 13 Exp.18 - Ethylylation and oxidation of the 10a-H epimeric ketones www.jonathanpmiller.com /Anthracycline_chemistry.htm   (1577 words)

Synthesis of 8-Hydroxyanthracycline The C-10R derivative still remained effective as an antileukaemic agent where as the C-10S epimer was ineffective. The anticipated C-10R epimer (16) was not the major epimer in this instance. The C-10aS epimer (6) is thought to arise by way of extensive C-10a base catalysed enolisation. www.jonathanpmiller.com /8hydroxyidarubicin   (1079 words)

Vitamin E Information The 1950's thalidomide disaster with numerous severe birth defects is a common example of d- vs l- epimer forms type problem with synthesized racemic mixtures. Information on any side effects of the synthetic vitamin E epimers is not readily available. Naturopathic and orthomolecular medicine advocates have long considered the synthetic vitamin E forms to be with little or no merit for cancer, circulatory and heart diseases. vitamine.researchtoday.net /about-vitamine.htm   (3665 words)

EPA: Federal Register: Lambda-Cyhalothrin; Pesticide Tolerances There are now validated methods to distinguish parent from epimer, and the tolerances will now be expressed as the combined residues of lambda- cyhalothrin and its epimer. In addition, EPA has concluded that although the Chemical Abstract Services (CAS) names for lambda- cyhalothrin and its epimer are more compact, to a chemist the structures are more easily derived from the IUPAC names. Tolerances to expire on November 15, 1997, are established for the combined residues of the pyrethroid lambda-cyhalothrin and its epimer expressed as: Lambda-cyhalothrin, a 1:1 mixture of (S)- www.epa.gov /docs/fedrgstr/EPA-PEST/1995/March/Day-27/pr-194.html   (2082 words)

Epimer - Encyclopedia, History, Geography and Biography   (Site not responding. Last check: 2007-10-17) In chemistry, an epimer is a stereoisomer that has a different configuration at only one of several stereogenic centers.For example, the sugars α- The -OH group on their fourth carbon has a different orientation. This encyclopedia, history, geography and biography article about Epimer contains research on www.arikah.net /encyclopedia/Epimer   (71 words)

Pastel BioScience - Epimer Technology   (Site not responding. Last check: 2007-10-17) The novel capture molecules are based on an engineered human scaffold protein, which is not antibody derived, that can be employed for the detection of protein based targets and therefore have applications in proteomics, diagnostics, functional genomics, therapeutics, biosensors and biopurification. Multiple capture molecules will be available immediately without the need for a physical selection process and importantly for proteomic screens the capture molecules can be multiplexed such that only a fraction of the number of capture molecules are required. As an example the 31,000 plus human proteins of the SwissProt database could potentially be identified with just 7,530 epimer capture molecules with a high degree of redundancy still built in to the system. www.newproductnetwork.co.uk /products/pastel.html   (479 words)

RSA 2003 Abstracts This study utilized a synthetic compound 20-oxo-5b-pregnan-3a-yl-carboxylic acid (PCA) that is structurally similar to pregnanolone and has been demonstrated to potentiate GABA currents and inhibit NMDA currents in electrophysiological studies using transfected cells in culture. The effects of PCA and an inactive epimer of this compound were tested on operant responding for ethanol prior to and following ethanol vapor exposure. The ability of PCA to alter ethanol intake appears to be related to actions of this compound on GABA neurotransmission, and the modulation of neuroactive steroid sites in the brain may be a potential target for treating alcoholism. www.scripps.edu /np/inia/abstractsRSA2003Scripps.html   (512 words)

LSD-25 Acid; Lysergide; d-lysergic acid diethylamide The amide lysergamide, a component of several varieties of morning glory seed, is also a controlled drug and, by law, a depressant. Most methods are faulted due to excessive moisture sensitivity, generation of side-products, or epimerization or inversion at the 8-position carbon to form d-iso-LSD. The epimer, inverted at C-8, is isoergine or d-isolysergamide, and is also a component of morning glory seeds. www.hallucinogens.com /lsd   (3630 words)

BioMed Central | Full text | Riboflavin synthase of Schizosaccharomyces pombe.Protein dynamics revealed by 19F NMR ... The signals of the free epimer A appeared broadened to 80 Hz – 100 Hz, whereas the signals of the ligand bound in different states had apparent line widths of 170 – 300 Hz. The 6-trifluoromethyl groups of 6-trifluoromethyl-7-oxo-8-ribityl-lumazine and 6,7-bis(trifluoromethyl)-8-ribityllumazine hydrate (epimer A) are topologically equivalent. In the mixture, epimer A displaced from the enzyme by the competing ligands had a linewidth of about 20 Hz. www.biomedcentral.com /1471-2091/4/18   (5987 words)

Amazon.com: epimer   (Site not responding. Last check: 2007-10-17) Tagatose is nearly identical (C-4 epimer) to D-fructose, the common simple... daunorubicin, while epirubicin is an epimer at the 4'-position of the... The Structure of Leocardin, two epimers of a Diterpenoid from Leonurus... www.amazon.com /s?ie=UTF8&keywords=epimer&tag=lexico&index=blended&link_code=qs&page=1   (1056 words)

United States Patent Epimerization at C-17 and optical rotatory dispersion Study of C/D cis pregnane-2-one derivatives", Steroids. The acetone was evaporated and the aqueous layer extracted with chloroform (3.times.20 ml), the chloroform layer was dried (MgSO.sub.4), filtered and evaporated to give the epimeric trihydroxy steroids (15a, 15b) (42 mg, 61%). Separation of the epimeric mixture (15a, 15b) (15 mg) was achieved by flash chromatographic separation using chloroform:methanol (9:1 v/v) as the eluant to give the pure 17.beta.-epimer (15a), (10 mg), m.p. www.purehoodia.com /P57_Patent.htm   (14876 words)

Hey! Thanks for asking! According to the notes, however, D-gulose is the C-3 epimer of D-idose and the drawing that I had done correctly was in fact of D-mannose. Remember that it codes ("1,3"), which means that, in the Fischer, the OH's at carbons 2 and 4 are on the left. The epimer at C-2 of this sugar would code ("3"). darkwing.uoregon.edu /~jlong/wi04/332/voh.html   (1174 words)

SparkNotes: Carbohydrates: Terms Because of this unique difference, it is known as an epimer of glucose. Hydroxyl group - A chemical group consisting of an oxygen atom covalently bonded to a hydrogen atom. Since its electron density is greatest around the oxygen atom, the group has a polar character to its bond and is therefore either very hydrophilic or water soluble. www.sparknotes.com /health/carbohydrates/terms.html   (1668 words)

Biochem 153A: Week 4 Discussion Handout   (Site not responding. Last check: 2007-10-17) Objectives: Be able to draw Fischer and Haworth projection structures for glucose; Know the epimers mannose and galactose (fructose, too); Understand carbohydrate enantiomers, anomers, and glycosidic linkages. The sugar family is a bunch of carbohydrates that exist as enantiomers. However, it is not an epimer of glucose. www.chem.ucla.edu /~wong/153/week4.html   (245 words)

ARS | Publication request: Dft Study of a and B-D-Galactopyranose at the B3lyp/6-311++g** Level of Theory Interpretive Summary: This work is a continuation of high level theoretical studies of a series of epimers of glucose. In this paper we present electronic structural characterization of D-galactopyranose, and epimer of D-glucose in which the four position hydroxyl group is moved from the equatorial to the axial configuration. Technical Abstract: Forty-one conformations of alpha- and Beta-D-galactopyranose, the C-4 substituted epimer of glucopyranose, were geometry optimized using the B3LYP density functional and the 6-311++G** basis set. ars.usda.gov /research/publications/publications.htm?SEQ_NO_115=186051   (410 words)

Colon or ileum-specific steroid derivatives - Patent 5908833 The 1,2-position of the GCS.sup.1 is a saturated or a double bond. The acetal I is in epimerically pure form i.e. the acetal I is the corresponding pure 22R-epimer, IA, or 22S-epimer, IB ##STR3## or is in the form of an epimeric mixture. www.freepatentsonline.com /5908833.html   (4469 words)

Perkin Transactions 1 Articles -dimethoxyphenyl)-2,5-dimethyl-1,3-dioxolane 7 with titanium tetrachloride affords rel-(1R,3R,4S)-4-hydroxy-6,8-dimethoxy-1,3-dimethylisochromane 19 and its C-1 epimer 20 in high yield. -dimethoxyphenyl)-2,5-dimethyl-1,3-dioxolanes 8 and 9 gives rel-(1R,3R,4R)-4-hydroxy-6,8-dimethoxy-1,3-dimethylisochromane 29 and its C-1 epimer 31, with the latter predominating at both —78 and —30 °C. At 0 °C, dioxolane 7 is isomerised to rel-(1S,1 -hydroxyethyl)-4,6-dimethoxy-3-methyl-1,3-dihydroisobenzofuran 25 and its C-3 epimer 26 as the sole reaction products in a 10 : 1 ratio. www.rsc.org /Publishing/Journals/P1/article.asp?doi=P19960002241   (136 words)

Sulfation of Budesonide by Human Cytosolic Sulfotransferase, Dehydroepiandrosterone-Sulfotransferase (DHEA-ST) -- ...   (Site not responding. Last check: 2007-10-17) Previous in vitro studies with human liver microsomes have demonstrated that the budesonide epimers are differentially metabolized This study investigates the ability of the human SULTs to conjugate the epimers of budesonide. Ryrfeldt A, Edsbacker S and Pauwels R (1984) Kinetics of the epimeric glucocorticoid budesonide. dmd.aspetjournals.org /cgi/content/full/30/5/582   (3238 words)

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