- Investigations of the Alignment Process of PBPMLG: 2H NMR Analysis Reveals a Thermoresponsive 90° Flip of the Polymer
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The application of anisotropic parameters in NMR-spectroscopy enables the acquisition of spatial and angular information, complementary to those from conventional isotropic NMR-measurements. The use of alignment media is a well-established method for inducing anisotropy. PBPMLG is a recently discovered polyglutamate-based alignment medium, exhibiting thermoresponsive behavior in the lyotropic liquid crystalline (LLC) phase, thus offering potential for deeper understanding of the alignment process. We present one approach for investigating the thermoresponsive behavior by synthesizing specifically deuterated PBPMLG-isotopologues and their subsequent analyses using 2H NMR-spectroscopy. It was possible to relate the observed thermoresponsive behavior to a flip of the polymer with respect to the external magnetic field—an effect never observed before in glutamate-based polymeric alignment media. Furthermore, a solvent-induced temperature dependent gelation was verified in THF, which might provide yet another opportunity to manipulate the properties of this alignment medium in the future.
- Hirschmann, Max,Lehmann, Matthias,Radulov, Iliya A.,Schirra, Dominic S.,Thiele, Christina M.
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supporting information
p. 21040 - 21046
(2021/08/23)
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- A novel strategy for efficient chemoenzymatic synthesis of D-glutamine using recombinant Escherichia coli cells
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D-glutamine is a D type stereoisomer of glutamine which is involved in many metabolic processes. Seeking lower-cost and industrially scalable approaches for the synthesis of D-glutamine is very valuable both in academic career and potential applications. Herein, we developed a novel efficient chemoenzymatic strategy for producing D-glutamine. Initially, DL-glutamine was chemically prepared with cheap and accessible DL-glutamic acid as raw material. Subsequently, the L-glutamine among the racemic mixture was selectively hydrolyzed to L-glutamic acid by Escherichia coli whole-cell system which expressed L-aminopeptidase D-Ala-esterase/amidase (DmpA) from Ochrobactrum anthropi. The left D-glutamine was obtained by isoelectric point precipitation with 70% of the theoretical yield. Furthermore, we optimized enzymatic resolution conditions to determine the optimum parameters as pH 8, 30 °C, 0.1% (v/v) Triton X-100, and 1 mM Mn2+. These results suggested that our strategy might be potentially usable for the synthesis of D-glutamine in industrial productions.
- Du, Qinglin,Zhang, Xiangyang,Pan, Xinru,Zhang, Hongjuan,Yang, Yu-Shun,Liu, Junzhong,Jiao, Qingcai
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- Synthesis method of phthalic acylamino-L-glutamic anhydride
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The invention discloses a synthesis method of phthalic acylamino-L-glutamic anhydride. The method comprises the following steps: firstly, ensuring that phthalic anhydride and L-glumatic acid react for4 to 8 hours at 80 to 85 DEG C with the existence of an acid-binding agent, and adjusting pH with hydrochloric acid till N-phthaloyl-L-glutamic acid is separated out; secondly, adding acetic anhydride to the N-phthaloyl-L-glutamic acid obtained in the first step, performing reflux reaction, naturally cooling to room temperature, ensuring that white solid is separated out, separating, and drying,so as to obtain the phthalic acylamino-L-glutamic anhydride. The synthesis method is short in route, easy to operate, high in yield, low in pollution, and more environmentally friendly, ensures that the production cost is greatly reduced, and has a good application prospect.
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Page/Page column 4; 5
(2019/03/29)
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- Poly-γ-p-Biphenylmethyl-Glutamate as Enantiodifferentiating Alignment Medium for NMR Spectroscopy with Temperature-Tunable Properties
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The use of anisotropic NMR parameters—especially residual dipolar couplings (RDCs)—offers access to additional structural information and, therefore, alignment media required for this approach are under a continuous development. Here, we present poly-γ-p-biphenylmethyl-glutamate (PBPMG) as a new versatile enantiodifferentiating alignment medium. The thermoresponsive properties of this polymer allowed for RDC measurements of more than one orientation within the same sample at different temperatures. Moreover, the outstanding enantiodifferentiation along with excellent spectral quality even offered the opportunity to differentiate enantiomers in mixtures.
- Jeziorowski, Sharon,Thiele, Christina M.
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p. 15631 - 15637
(2018/09/27)
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- Synthesis of amphiphilic alternating polyesters with oligo(ethylene glycol) side chains and potential use for sustained release drug delivery
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Novel amphiphilic alternating polyesters, poly((N-phthaloyl-l-glutamic anhydride)-co-(2-(2-(2-methoxyethoxy)ethoxy)methyl)oxirane) (P(PGA-co-ME 2MO)), were synthesized by alternating copolymerization of PGA and ME2MO. The structures of the synthesized polyesters were characterized by 1H NMR, 13C NMR, FT-IR, and GPC analyses. Because of the presence of oligo(ethylene glycol) (OEG) side chains, the polyesters could self-assemble into thermosensitive micelles. Dynamic light scattering (DLS) showed that these micelles underwent thermoinduced size decrease without intermicellar aggregation. In vitro methyl thiazolyl tetrazolium (MTT) assay demonstrated that the polyesters were biocompatible to Henrietta Lacks (HeLa) cells, rendering their potential for drug delivery applications. Two hydrophobic drugs, rifampin and doxorubicin (DOX), were loaded into the polyester micelles and observed to be released in a zero-order sustained manner. The sustained release could be accelerated in lower pH or in the presence of proteinase K, due to the degradation of the polyester under these conditions. Remarkably, in vitro cell experiments showed that the polyester micelles accomplished fast release of DOX inside cells and higher anticancer efficacy as compared with the free DOX. With enhanced stability during circulation condition and accelerated drug release at the target sites (e.g., low pH or enzyme presence), these novel polyesters with amphiphilic structures are promising to be used in sustained release drug delivery systems.
- Wang, Wei,Ding, Jianxun,Xiao, Chunsheng,Tang, Zhaohui,Li, Di,Chen, Jie,Zhuang, Xiuli,Chen, Xuesi
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experimental part
p. 2466 - 2474
(2012/04/23)
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- Novel Dipeptides incorporating selenoamino acids with enhanced bioavailability- Synthesis, pharmaceutical and cosmeceutical applications thereof
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Disclosed is a novel synthetic method for isomeric peptides through an appropriate linkage of L-selenomethionine or Se-Methyl-L-selenocysteine with L-glutamic acid. The novel synthetic method produces isomeric peptides of L-selenomethionine or Se-Methyl-L-selenocysteine that exhibit (i) enhanced water solubility; (ii) enhanced rate of dissolution in water; (iii) enhanced bioavailability; (iv) excellent vascular endothelial growth factor promoting activity; (v) excellent anti-5-alpha-reductase activity; (vi) capabilities to prevent/reduce “hair fall” and promote “hair growth”, thereby maintaining a perfect homeostasis for “hair care”. Cosmeceutical and pharmaceutical compositions comprising the isomeric peptides obtained through an appropriate linkage of L-selenomethionine or Se-Methyl-L-selenocysteine with L-glutamic acid are also disclosed. Other dipeptides with several other amino acids and uses thereof are also disclosed.
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Page/Page column 6
(2010/11/29)
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- γ-Glutamyl dipeptides in Petiveria alliacea
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Three γ-glutamyl dipeptides have been isolated from Petiveria alliacea L. roots. These dipeptides include (SC2RC7)- γ-glutamyl-S-benzylcysteine together with two diastereomeric sulfoxides, namely (SC2RC7RS)- and (SC2R C7RS)-γ-glutamyl-S-benzylcysteine S-oxides (γ-glutamyl-petiveriins A and B, respectively). Their structures and absolute configurations have been determined by NMR, MALDI-HRMS, IR and CD spectroscopy, and confirmed by comparison with authentic compounds obtained by synthesis.
- Kubec, Roman,Musah, Rabi A.
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p. 2494 - 2497
(2007/10/03)
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- Sulfur ylides 13. Synthesis and intramolecular cyclization of keto-stabilized sulfur ylides
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Keto-stabilized sulfur mono-and bisylides were obtained from N-phthalylglutamic acid and their intramolecular cyclization was studied. The intramolecular cyclization of the ylide obtained at the α-carboxy group gave a product of the pyrrolizidinedione structure; bisylide yielded a cycloheptene derivative as the result of intramolecular recombination of intermediate dicarbene. The ylide obtained at the γ-carboxy group underwent no cyclization, giving methylthio ketone and oxo benzoate.
- Galin,Sakhautdinov,Lakeev,Egorov,Fatykhov,Maidanova
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p. 2867 - 2872
(2007/10/03)
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- Synthesis of aza and oxaglutamyl-p-nitroanilide derivatives and their kinetic studies with γ-glutamyltranspeptidase
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A new series of L-glutamic acid p-nitroanilide analogues has been synthesized and tested as substrates and inhibitors of rat kidney γ-glutamyltranspeptidase (GGT). Kinetic parameters (Km and kcat) were determined for each analogue and provide insight into the scope and limits of GGT catalytic efficiency.
- Lherbet, Christian,Morin, Mylene,Castonguay, Roselyne,Keillor, Jeffrey W.
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p. 997 - 1000
(2007/10/03)
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- Thalidomide metabolites and analogues. 3. Synthesis and antiangiogenic activity of the teratogenic and TNFα-modulatory thalidomide analogue 2-(2,6-dioxopiperidine-3-yl)phthalimidine
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Versatile synthesis of the teratogenic, TNFα-modulatory, and antiangiogenic thalidomide analogue 2-(2,6-dioxopiperidine-3-yl)phthalimidine (1) and its direct antiangiogenic properties are described. With thalidomide or thalidomide derivatives as precursors, the synthesis involved either carbonyl reduction/thiation-desulfurization or carbonyl reduction/acyliminium ion reduction protocols. Compared to earlier studies with thalidomide, which was only active with microsomal treatment, 1 exhibited marginal inhibitory activity in the rat aortic ring assay, thereby demonstrating the requirement for metabolic activation.
- Luzzio, Frederick A.,Mayorov, Alexander V.,Ng, Sylvia S. W.,Kruger, Erwin A.,Figg, William D.
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p. 3793 - 3799
(2007/10/03)
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- Absolute configuration of α-phthalimido carboxylic acid derivatives from circular dichroism spectra
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It is demonstrated that the Cotton effects due to the 220 nm phthalimide π-π* transition observed for a series of derivatives of α- phthalimidocarboxylic acids unequivocally reflect the amino acid absolute configuration. This method is based on the exciton coupling of the allowed transitions of the phthalimide and the carboxylic acid derivative chromophores. (C) 1999 Elsevier Science Ltd.
- Skowronek,Gawronski
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p. 4585 - 4590
(2007/10/03)
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- Monodisperse liquid crystalline peptides
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Solid phase peptide synthesis (SPPS) has been used as a synthetic tool to prepare monodisperse mesogen-oligopeptide conjugates with novel molecular architectures. Building upon previous success in this area, we have extended our methodologies to include a mesogenically substituted L-glutamic acid residue, and incorporated this derivative, as well as the L-lysine derivative previously reported, into a variety of new structures. Some novel liquid crystalline materials have been discovered. Both α-helical and β-sheet secondary structures have been explored as alternative scaffolds for the pendant mesogenic groups. The helical systems show most promise in terms of their ease of synthesis and handling, but at the relatively lower levels of mesogenic substitution studied so far, compared to the previously reported homo-oligopeptide materials, mesophases are not observed. The β-sheet materials prepared are rather insoluble and too high melting to have any practical value as thermotropic materials without further manipulation of their structures.
- Cormack, Peter A. G.,Moore, Barry D.,Sherrington, David C.
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p. 1977 - 1983
(2007/10/03)
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- Synthesis of 3-methylaspartic acids by ring-contraction of a nickelacycle derived from glutamic anhydride
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The synthesis of protected methylaspartic acids from glutamic acid has been achieved by means of ring contraction of the derived nickelacycle followed by insertion of isocyanides.
- Echavarren, Antonio M.,Castano, Ana M.
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p. 2369 - 2378
(2007/10/02)
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