- Unique polyhalogenated peptides from the marine sponge Ircinia sp.
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Two new bromopyrrole peptides, haloirciniamide A (1) and seribunamide A (2), have been isolated from an Indonesian marine sponge of the genus Ircinia collected in the Thousand Islands (Indonesia). The planar structure of both compounds was assigned on the basis of extensive 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configuration of the amino acid residues in 1 and 2 was determined by the application of Marfey's method. Compound 1 is the first dibromopyrrole cyclopeptide having a chlorohistidine ring, while compound 2 is a rare peptide possessing a tribromopyrrole ring. Both compounds failed to show significant cytotoxicity against four human tumor cell lines, and neither compound was able to inhibit the enzyme topoisomerase I or impair the interaction between programmed cell death protein PD1 and its ligand, PDL1.
- Fernández, Rogelio,Bayu, Asep,Hadi, Tri Aryono,Bueno, Santiago,Pérez, Marta,Cuevas, Carmen,Putra, Masteria Yunovilsa
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- Colony-wise Analysis of a Theonella swinhoei Marine Sponge with a Yellow Interior Permitted the Isolation of Theonellamide i
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There are several examples of marine organisms whose metabolic profiles differ among conspecifics inhabiting the same region. We have analyzed the metabolic profile of each colony of a Theonella swinhoei marine sponge with a yellow interior and noticed the patchy distribution of one metabolite. This compound was isolated and its structure was studied by a combination of spectrometric analyses and chemical degradation, showing it to be a congener in the theonellamide class of bicyclic peptides. Theonellamides had previously been isolated by us only from T. swinhoei with a white interior and not from those with a yellow interior.
- Fukuhara, Kazuya,Takada, Kentaro,Watanabe, Ryuichi,Suzuki, Toshiyuki,Okada, Shigeru,Matsunaga, Shigeki
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p. 2595 - 2599
(2018/12/13)
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- Chemical evolution of simple amino acids to asparagine under discharge onto the primitive hydrosphere: Simulation experiments using contact glow discharge
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Asparagine is an important amino acid for abiotic polypeptide synthesis. In simulation experiments, it was obtained in 3.0% yield (based on the amount of consumed alanine) from alanine (100 mM) and formamide (200 mM) by contact glow discharge (Harada discharge) onto aqueous solutions. The present results suggest that asparagine could be abiotically synthesized from simple amino acids under possible primitive earth conditions.
- Munegumi, Toratane
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p. 1208 - 1215
(2015/02/19)
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- Total synthesis of nominal (11S)- and (11R)-cyclocinamide A
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The cyclocinamides possess a unique β2αβ 2α 14-membered tetrapeptide core. The initially reported biological data and intriguing structure, which was without full stereochemical identification, necessitated synthesis of both nominal (all-S) cyclocinamide A and the 11R isomer. The completed synthesis is highlighted by the use of a (cyclo)asparagine-containing dipeptide as a turn inducing fragment. Due to inconsistencies in analytical data between natural and synthetic samples, a re-evaluation of the natural product stereochemistry appears necessary.
- Garcia, Jessica M.,Curzon, Stephanie S.,Watts, Katharine R.,Konopelski, Joseph P.
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supporting information; experimental part
p. 2054 - 2057
(2012/06/29)
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- Abiotic asparagine formation from simple amino acids by contact glow discharge electrolysis
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Asparagine, one of the most important amino acids for prebiotic peptide formation in aqueous media, was formed using Contact Glow Discharge Electrolysis (CGDE) against aqueous solutions containing simple amino acids and carboxylic acid amides.
- Munegumi, Toratane,Shimoyama, Akira,Harada, Kaoru
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p. 393 - 394
(2007/10/03)
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- Etude par la Modelisation Moleculaire de la Regioselectivite de l'Ouverture des Acides Glycidiques par les Amines Aliphatiques
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A model for glycidic acids opening reaction by ammonia and amines has been suggested from semi-empiric orbital calculations.It provides a way for evaluating the different interactions between the incoming nucleophile and the oxirane substituents.Steric and coulombic interactions of the carboxylate in staggered conformation (cis substitution) has a major influence to rationalize experimental regioselectivity.
- Grosjean, F.,Huche, M.,Larcheveque, M.,Legendre, J. J.,Petit, Y.
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p. 9325 - 9334
(2007/10/02)
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- Fixation of Molecular Nitrogen Using Aliphatic Carboxylic Acid by Nitrogen Arc Plasma. Formation of Amino Acids
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When argon-nitrogen plasma was blown into an aqueous solution containing aliphatic carboxylic acids, formation of several amino acids and amines was identified.
- Takasaki, Michiaki,Harada, Kaoru
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p. 365 - 368
(2007/10/02)
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- Oxidation reaction of aliphatic amines and aminoalcohols in aqueous solution induced by argon arc plasma
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Argon arc plasma induced a powerful and stepwise oxidation reaction including conversion of methyl group to carboxyl group, oxidative cleavage of carbon-carbon bond, and oxidative deamination. Main active species were considered to be hydroxyl radicals by decomposition of water molecules.
- Takasaki, Michiaki,Harada, Kaoru
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p. 4463 - 4473
(2007/10/02)
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- FORMATION OF AMINO ACIDS FROM ALIPHATIC AMINES BY CONTACT GLOW DISCHARGE ELECTROLYSIS
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Oxidation of aliphatic amines in an aqueous solution by contact glow discharge electrolysis resulted in the formation of several amino acids, which was explained by the oxidative action of hydroxyl radical generated by the electric discharge process to the aqueous solution.
- Harada, Kaoru,Nomoto, Masayo M.,Gunji, Hiromi
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p. 769 - 772
(2007/10/02)
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- OXIDATIVE DEGRADATION OF β- AND γ-AMINO ACIDS BY CONTACT GLOW DISCHARGE ELECTROLYSIS
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The degradation of β- and γ-amino acids in aqueous solutions by contact glow discharge electrolysis (CGDE) was studied.It was found that the reaction is actually a stepwise oxidative degradation by hydroxyl radical produced by CGDE.
- Harada, Kaoru,Terasawa, Jun-ichi
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p. 441 - 444
(2007/10/02)
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