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Cserháti T 《Biomedical chromatography : BMC》2007,21(8):780-796
The newest results in the application of various chromatographic methods (gas-liquid chromatography, liquid chromatographic techniques, electrically driven systems) for the separation and quantitative determination of amino acids and short peptides in pure state and in complicated matrices are compiled. The results are concisely described and critically evaluated. The future trends of the chromatographic analysis of amino acids and short peptides are briefly discussed. 相似文献
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Direct asymmetric intermolecular aldol reactions catalyzed by amino acids and small peptides 总被引:1,自引:0,他引:1
Córdova A Zou W Dziedzic P Ibrahem I Reyes E Xu Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(20):5383-5397
In nature there are at least nineteen different acyclic amino acids that act as the building blocks of polypeptides and proteins with different functions. Here we report that alpha-amino acids, beta-amino acids, and chiral amines containing primary amine functions catalyze direct asymmetric intermolecular aldol reactions with high enantioselectivities. Moreover, the amino acids can be combined into highly modular natural and unusual small peptides that also catalyze direct asymmetric intermolecular aldol reactions with high stereoselectivities, to furnish the corresponding aldol products with up to >99 % ee. Simple amino acids and small peptides can thus catalyze asymmetric aldol reactions with stereoselectivities matching those of natural enzymes that have evolved over billions of years. A small amount of water accelerates the asymmetric aldol reactions catalyzed by amino acids and small peptides, and also increases their stereoselectivities. Notably, small peptides and amino acid tetrazoles were able to catalyze direct asymmetric aldol reactions with high enantioselectivities in water, while the parent amino acids, in stark contrast, furnished nearly racemic products. These results suggest that the prebiotic oligomerization of amino acids to peptides may plausibly have been a link in the evolution of the homochirality of sugars. The mechanism and stereochemistry of the reactions are also discussed. 相似文献
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Yang J Alemany LB Driver J Hartgerink JD Barron AR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(9):2530-2545
A series of [60]fullerene-substituted phenylalanine (Baa) and lysine derivatives have been prepared by the condensation of 1,2-(4'-oxocyclohexano)fullerene with the appropriately protected (4-amino)phenylalanine and lysine, respectively. Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. The reduction of the imine is not accompanied by hydroboration of the fullerene cage. The [70]fullerene phenylalanine derivative has also been prepared as have the di-amino acid derivatives. The compounds were characterized by MALDI-TOF mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry. 1H and 13C NMR spectroscopy allowed the observation of diastereomers. Fullerene-substituted peptides may be synthesized on relatively large scale by solid-phase peptide synthesis. The presence of the C60-substituted amino acid in a peptide has a significant effect on the secondary structures and self-assembly properties of peptides as compared to the native peptide. The antioxidant assay of Baa and a Baa-derived anionic peptide was determined to be significantly more potent than Trolox. 相似文献
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Andrey A. Karasik Igor O. Georgiev Elvira I. Musina Oleg G. Sinyashin Joachim Heinicke 《Polyhedron》2001,20(28):666-3331
Acyclic and cyclic amino acid derivatives of 2-phosphinophenols have been synthesised by reaction of primary phosphinophenols (4-R-2-H2PC6H3OH; R=H, Me, OMe) 1a–c with formaldehyde and amino acids (o- and p-aminobenzoic acid,
-lysine) via in situ formed hydroxymethyl species 2a–c. Condensation reactions with glycine did not afford defined products except when the methoxymethyl and tetrahydropyranyl ethers of 1d,e were used instead of the hydroxy compounds. o-Aminobenzoic acid gives rise to linear bis(o-carboxyphenylaminomethyl)phosphines 3a–e. p-Aminobenzoic acid, dependent on the molar ratio, affords bis(p-carboxyphenylaminomethyl)phosphines 4a,d as well as eight-membered heterocyclic 1,5,3,7-diazadiphosphacyclooctanes 5a–e. The aliphatic amino acids glycine and
-lysine form six-membered heterocyclic 1,3,5-diazaphosphorinanes 6d and 7a–e, respectively, in presence of excess formaldehyde.
-lysine differs from glycine by reaction at the terminal amino group. The structures of the compounds have been elucidated by multinuclear NMR spectroscopy. The salts of the phosphino amino acids are soluble in water. Water solubility increases with the number of hydrophilic groups, i.e. free phenols are more soluble than their ethers. Ligand concentrations in water from 0.1 to 1 M were observed. 相似文献
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Tushar Kanti Chakraborty Pothukanuri Srinivasu Subhasish Tapadar Bajjuri Krishna Mohan 《Journal of Chemical Sciences》2004,116(4):187-207
To meet the growing demands for the development of new molecular entities for discovering new drugs and materials, organic
chemists have started working on many new concepts that can help to assimilate knowledge-based structural diversities more
efficiently than ever before. Emulating the basic principles followed by Nature to build its vast repertoire of biomolecules,
organic chemists are developing many novel multifunctional building blocks and using them to create ‘nature-like’ and yet
unnatural organic molecules. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl,
amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature’s
molecular arsenal. In recent years, sugar amino acids have been used extensively in the area of peptidomimetic studies. Advances
made in the area of combinatorial chemistry can provide the necessary technological support for rapid compilations of sugar
amino acidbased libraries exploiting the diversities of their carbohydrate frameworks and well-developed solid-phase peptide
synthesis methods. This perspective article chronicles some of the recent applications of various sugar amino acids, furan
amino acids, pyrrole amino acids etc. and many other related building blocks in wide-ranging peptidomimetic studies 相似文献
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Dipl.‐Chem. K. Philip Wojtas Dr. Matthias Riedrich Dr. Jin‐Yong Lu Dr. Philipp Winter M. Sc. Thomas Winkler M. Sc. Sophia Walter Prof. Dr. Hans‐Dieter Arndt 《Angewandte Chemie (International ed. in English)》2016,55(33):9772-9776
Total synthesis of the bismacrocyclic thiopeptide antibiotic nosiheptide was achieved through the assembly of a fully functionalized linear precursor followed by consecutive macrocyclizations. Key features are a critical macrothiolactonization and a mild deprotection strategy for the 3‐hydroxypyridine core. The natural product was identical to isolated authentic material in terms of spectral data and antibiotic activity. 相似文献
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Park H Nandhakumar R Hong J Ham S Chin J Kim KM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(32):9935-9942
(S)-2-Hydroxy-2'-(3-phenyluryl-benzyl)-1,1'-binaphthyl-3-carboxaldehyde (1) forms Schiff bases with a wide range of nonderivatized amino acids, including unnatural ones. Multiple hydrogen bonds, including resonance-assisted ones, fix the whole orientation of the imine and provoke structural rigidity around the imine C==N bond. Due to the structural difference and the increase in acidity of the alpha proton of the amino acid, the imine formed with an L-amino acid (1-l-aa) is converted into the imine of the D-amino acid (1-D-aa), with a D/L ratio of more than 10 for most amino acids at equilibrium. N-terminal amino acids in dipeptides are also predominantly epimerized to the D form upon imine formation with 1. Density functional theory calculations show that 1-D-Ala is more stable than 1-L-Ala by 1.64 kcal mol(-1), a value that is in qualitative agreement with the experimental result. Deuterium exchange of the alpha proton of alanine in the imine form was studied by (1)H NMR spectroscopy and the results support a stepwise mechanism in the L-into-D conversion rather than a concerted one; that is, deprotonation and protonation take place in a sequential manner. The deprotonation rate of L-Ala is approximately 16 times faster than that of D-Ala. The protonation step, however, appears to favor L-amino acid production, which prevents a much higher predominance of the D form in the imine. Receptor 1 and the predominantly D-form amino acid can be recovered from the imine by simple extraction under acidic conditions. Hence, 1 is a useful auxiliary to produce D-amino acids of industrial interest by the conversion of naturally occurring L-amino acids or relatively easily obtainable racemic amino acids. 相似文献
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Vommina V. Sureshbabu Rao Venkataramanarao Shankar A. Naik G. Chennakrishnareddy 《Tetrahedron letters》2007,48(39):7038-7041
An efficient synthesis of tetrazole analogues of amino acids starting from Nα-Fmoc amino acid in a three-step protocol is reported. The free amino tetrazoles were obtained in good yields and with excellent purity after removal of the Fmoc group. The synthesis of analogues of aspartic and glutamic acids in which the 5-tetrazolyl moiety is inserted at the β/γ carboxyl group starting from Fmoc-Asn and Fmoc-Gln and the incorporation of these tetrazoles into peptides are also described. 相似文献
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《International journal of quantum chemistry》2018,118(3)
The existence and gas phase stability of silicon analogues of three natural amino acids (i.e., silicon glycine, silicon alanine, and silicon valine) belonging to the novel class of compounds termed silicon amino acids (SiAA) are investigated theoretically on the basis of ab initio QCISD/aug‐cc‐pVTZ and MP2/aug‐cc‐pVTZ calculations. All molecules studied (in their gas phase canonical forms) are structurally comparable to their proteinogenic counterparts (i.e., glycine, l ‐alanine, and l ‐valine) and capable of forming several structural isomers as such. These higher energy isomers are characterized by small relative energies (not exceeding 4 kcal mol−1). The simulated IR spectra of the Si‐Gly, Si‐Ala, and Si‐Val global minima are also presented and discussed. 相似文献
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Stefania De Luca 《Tetrahedron letters》2005,46(39):6637-6640
A synthetic strategy to prepare o-NBS protected Fmoc-amino acids under mild conditions, in a rapid and efficient way, characterised by high yields and excellent purity of the final products has been developed. The o-NBS protected Fmoc-amino acids are employed in solid phase peptide synthesis to prepare peptidomimetics carrying mono-benzylated moieties on peptide side chains. 相似文献
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Ming Kai Wei Zhang Huan Xie Liwei Liu Sujie Huang Xiao Li Zhengzheng Zhang Yuyang Liu Bangzhi Zhang Jingjing Song Rui Wang 《中国化学快报》2018,29(7):1163-1166
Conformational flexibility induced by proline and aminocaproic acid can increase anticancer activity and antimicrobial activity of dimeric antimicrobial peptides with reduced hemolytic activity. This study will contribute to the design of efficient antimicrobial peptides. 相似文献
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Precise theoretical predictions of NMR parameters are helpful for the spectroscopic identification of complicated biological molecules, especially for the carbon shielding tensors in amino acids. The (13)C shielding tensors of various crystalline amino acids and peptides have been calculated using the gauge-including projector augmented wave (GIPAW) method based on two different periodic structure models, namely that deduced from available crystallographic data and that from theoretically optimized structures. The incorporation of surrounding lattice effects is found to be crucial in obtaining reliable predictions of (13)C shielding tensors that are comparable to the experimental data. This is accomplished by refining the experimental crystallographic data of the amino acids and peptides at the GGA/PBE level by which more accurate intramolecular C--H bond lengths and intermolecular hydrogen-bonding interactions are obtained. Accordingly, more accurate predictions of (13)C shielding tensors comparable to the experimental results (within a maximum deviation of +/-10 ppm) were achieved, rendering more explicit (13)C shielding tensors assignments for solid biological systems particularly for amino acids with multiple carboxyl carbons, such as asparagine, glutamine, and glutamic acid. 相似文献
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Applications of hydrophilic interaction chromatography to amino acids,peptides, and proteins 下载免费PDF全文
This review summarizes the recent advances in the analysis of amino acids, peptides, and proteins using hydrophilic interaction chromatography. Various reports demonstrate the successful analysis of amino acids under such conditions. However, a baseline resolution of the 20 natural amino acids has not yet been published and for this reason, there is often a need to use mass spectrometry for detection to further improve selectivity. Hydrophilic interaction chromatography is also recognized as a powerful technique for peptide analysis, and there are a lot of papers showing its applicability for proteomic applications (peptide mapping). It is expected that its use for peptide mapping will continue to grow in the future, particularly because this analytical strategy can be combined with reversed‐phase liquid chromatography, in a two‐dimensional setup, to reach very high resolving power. Finally, the interest in hydrophilic interaction chromatography for intact proteins analysis is less evident due to possible solubility issues and a lack of suitable hydrophilic interaction chromatography stationary phases. To date, it has been successfully employed only for the characterization of membrane proteins, histones, and the separation of glycosylated isoforms of an intact glycoprotein. From our point of view, the number of hydrophilic interaction chromatography columns compatible with intact proteins (higher upper temperature limit, large pore size, etc.) is still too limited. 相似文献