scholarly journals Sorption of peptides and amino acids by ion exchangers

2021 ◽  
Vol 57 (3) ◽  
pp. 278-285
Author(s):  
Z. I. Kuvaeva ◽  
E. G. Karankevich
Keyword(s):  
Amino Acids ◽  
Cation Exchanger ◽  
Ion Exchangers ◽  
Oh Groups ◽  
Wide Range ◽  
Equilibrium Concentrations

Sorbtion of dipeptides leucylisoleucine, threonylthreonine and their monomeric amino acids leucine and threonine by anionite AV-17 and cationite KU-2-8 in a wide range of equilibrium concentrations has been studied. It was shown that the presence of hydrophilic OH-groups in the threonine molecule promotes superequivalent sorbtion of threonine on the cation exchanger. The presence of an OH-groups in the side chein of the dipeptide practically does not affect the sorbtion an KU-2-8. Sorbtion of dipeptides on AV-17-8 is higher in comparison with their monomeric amino acids.

scholarly journals Inorganic Nanostructured Anion-Exchange Materials Based on Aluminum Hydroxide

2020 ◽  
Vol 4 (3) ◽  
Keyword(s):  
Anion Exchange ◽  
Aluminum Hydroxide ◽  
Solid Phase ◽  
Structural Motif ◽  
Dynamic Mode ◽  
Isomorphic Substitution ◽  
Ion Exchangers ◽  
Oh Groups ◽  
Wide Range ◽  
Exchange Properties

Inorganic sorbents, in comparison with ordinary organic ion exchangers, have higher selectivity, radiation, thermal, and chemical stability. Inorganic ion exchangers are universal materials exhibiting both cation exchange and anion exchange properties. In this work, using aluminum hydroxide (AHO) as an example, we study the possibility of expanding the range of metal oxyhydrates that can serve as the basis to produce inorganic anion-exchange materials. The properties of aluminum hydroxide largely depend on the method of its production. This phenomenon is associated with a different state of Al3+ ions in aqueous solutions during hydrolysis. Estimation of the size of the primary particles of hydrated alumina gives a value of 19 nm. The most potent effect on the structure and ion-exchange properties of aluminum hydroxide is exerted by the introduction of alloying elements into its composition. Isomorphic substitution of a part of Al(III) ions in the structure of aluminum hydroxide with ions with a higher charge (Ti(IV), Zr(IV), or W(VI)) leads to an increase in the content of exchangeable OH-groups in the resulting material. The synthesized materials are amorphous substances, to study their structure; the method of diffuse X-ray scattering was used. The Gibbsite structural motif is determined, and structural changes occurring under the influence of various factors, and synthesis conditions are analyzed. By optimizing the composition of the material, it is possible to improve its sorption characteristics significantly. AAW-0, AAZ-0, and AAT-0 anion exchangers synthesized based on hydrated aluminum oxide can be used to purify weakly acidic electrolyte solutions from anionic impurities in the dynamic mode of repeated sorptiondesorption cycles. Materials based on mixed hydrated oxides of various elements can also be used as catalyst supports. Their anion exchange properties allow a wide range to vary the number of different anions introduced into the solid phase and, accordingly, to regulate the number and state of active catalytic sites.

scholarly journals Bilayer capillary coatings based on nanosized ion-exchangers for the capillary electrochromatography analyses of biogenic amines and amino acids

2021 ◽  
Vol 25 (3) ◽  
pp. 230-240
Author(s):  
D. V. Makeeva ◽  
◽  
D. A. Polikarpova ◽  
L. A. Kartsova ◽  
◽  
...  
Keyword(s):  
Amino Acids ◽  
Functional Groups ◽  
Capillary Electrochromatography ◽  
Cation Exchanger ◽  
Physical Adsorption ◽  
Stationary Phases ◽  
Layer By Layer ◽  
Ion Exchangers ◽  
High Concentration ◽  
Capillary Walls

Nanoparticles are widely used in capillary electrophoresis as stationary phases adsorbed on the internal capillary walls for the separation and concentration of analytes in capillary electrochromatography. The fastest and simplest approach for the formation of coatings is a physical adsorption of nanoparticles. Nevertheless, the formed coatings frequently possess low stability. The layer-by-layer approach for the formation of stabile and dense coating of internal capillary walls based on negatively charged nanosized cation-exchanger was proposed. The method included the sequential alteration of appositively charged layers of nanosized ion-exchangers. The proposed “anion-exchanger – cation-exchanger” bilayer coating possesses high stability in wide pH range (2-10) and provides up to 120 analyses without the need of re-coating. The coating was applied for the separation and on-line concentration of catecholamines and amino acids in capillary electrochromatography mode. High efficiencies were achieved (N = 450-720 th. t.p./m and N = 400-520 th. t.p./m for cathecholamies and amino acids, respectively), while the analysis time was significantly decreased. It was established, that high concentration of negatively charged functional groups on the capillary surface led to the increase of stacking efficiency factors due to the interactions between analytes and functional groups of the modifier on the capillary walls. It contributed to the 2-4 times reduced detection limits (LODs) of analytes compared to the mono-layer coatings (LODs of catecholamines = 3-4 ng/mL, LODs of amino acids = 40-100 ng/mL).

Cucurbitacins as Anticancer Agents: A Patent Review

2019 ◽  
Vol 14 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Hidayat Hussain ◽  
Ivan R. Green ◽  
Muhammad Saleem ◽  
Khanzadi F. Khattak ◽  
Muhammad Irshad ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Wide Spectrum ◽  
Biological Effects ◽  
Therapeutic Effects ◽  
Cytotoxic Effects ◽  
Natural Sources ◽  
Oh Groups ◽  
Drug Candidates ◽  
The Past ◽  
Wide Range

Background: Cucurbitacins belong to a group of tetracyclic triterpenoids that display a wide range of biological effects. In the past, numerous cucurbitacins have been isolated from natural sources and many active compounds have been synthesized using the privileged scaffold in order to enhance its cytotoxic effects. Objective: his review covers patents on the therapeutic effects of natural cucurbitacins and their synthetic analogs published during the past decade. By far, the majority of patents published are related to cancer and Structure-Activity Relationships (SAR) of these compounds are included to lend gravitas to this important class of natural products. Methods: The date about the published patents was downloaded via online open access patent databases. Results: Cucurbitacins display significant cytotoxic properties, in particular cucurbitacins B and D which possess very potent effects towards a number of cancer cells. Numerous cucurbitacins isolated from natural sources have been derivatized through chemical modification at the C(2)-OH and C(25)- OH groups. Most importantly, an acyl ester of the C(25)-OH and, iso-propyl, n-propyl and ethyl ether groups of the C(2)-OH demonstrated the most increased cytotoxic activity. Conclusion: The significant cytotoxic effects of natural and semi-synthetic cucurbitacins make them attractive as new drug candidates. Moreover, cucurbitacins have the capability to form conjugates with other anticancer drugs which will synergistically enhance their anticancer effects. The authors believe that in order to get lead compounds, there should be a greater focus on the synthesis of homodimers, heterodimers, and halo derivatives of cucurbitacins. In the opinion of the authors the analysis of the published patents on the cucurbitacins indicates that these compounds can be developed into a regimen to treat a wide spectrum of cancers.

scholarly journals Autophagy Deficiency by Atg4B Loss Leads to Metabolomic Alterations in Mice

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 481
Author(s):  
Gemma G. Martínez-García ◽  
Raúl F. Pérez ◽  
Álvaro F. Fernández ◽  
Sylvere Durand ◽  
Guido Kroemer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Mammalian Cells ◽  
Tissue Homeostasis ◽  
In Vivo Studies ◽  
Protective Mechanism ◽  
Cardiac Damage ◽  
Wide Range ◽  
First Time

Autophagy is an essential protective mechanism that allows mammalian cells to cope with a variety of stressors and contributes to maintaining cellular and tissue homeostasis. Due to these crucial roles and also to the fact that autophagy malfunction has been described in a wide range of pathologies, an increasing number of in vivo studies involving animal models targeting autophagy genes have been developed. In mammals, total autophagy inactivation is lethal, and constitutive knockout models lacking effectors of this route are not viable, which has hindered so far the analysis of the consequences of a systemic autophagy decline. Here, we take advantage of atg4b−/− mice, an autophagy-deficient model with only partial disruption of the process, to assess the effects of systemic reduction of autophagy on the metabolome. We describe for the first time the metabolic footprint of systemic autophagy decline, showing that impaired autophagy results in highly tissue-dependent alterations that are more accentuated in the skeletal muscle and plasma. These changes, which include changes in the levels of amino-acids, lipids, or nucleosides, sometimes resemble those that are frequently described in conditions like aging, obesity, or cardiac damage. We also discuss different hypotheses on how impaired autophagy may affect the metabolism of several tissues in mammals.

scholarly journals Recent Advances in Fabrication of Non-Isocyanate Polyurethane-Based Composite Materials

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3497
Author(s):  
Piotr Stachak ◽  
Izabela Łukaszewska ◽  
Edyta Hebda ◽  
Krzysztof Pielichowski
Keyword(s):  
Raw Materials ◽  
Synthesis Method ◽  
Polymeric Materials ◽  
Original Research ◽  
Significant Group ◽  
Oh Groups ◽  
New Class ◽  
Hazardous Chemical ◽  
Wide Range

Polyurethanes (PUs) are a significant group of polymeric materials that, due to their outstanding mechanical, chemical, and physical properties, are used in a wide range of applications. Conventionally, PUs are obtained in polyaddition reactions between diisocyanates and polyols. Due to the toxicity of isocyanate raw materials and their synthesis method utilizing phosgene, new cleaner synthetic routes for polyurethanes without using isocyanates have attracted increasing attention in recent years. Among different attempts to replace the conventional process, polyaddition of cyclic carbonates (CCs) and polyfunctional amines seems to be the most promising way to obtain non-isocyanate polyurethanes (NIPUs) or, more precisely, polyhydroxyurethanes (PHUs), while primary and secondary –OH groups are being formed alongside urethane linkages. Such an approach eliminates hazardous chemical compounds from the synthesis and leads to the fabrication of polymeric materials with unique and tunable properties. The main advantages include better chemical, mechanical, and thermal resistance, and the process itself is invulnerable to moisture, which is an essential technological feature. NIPUs can be modified via copolymerization or used as matrices to fabricate polymer composites with different additives, similar to their conventional counterparts. Hence, non-isocyanate polyurethanes are a new class of environmentally friendly polymeric materials. Many papers on the matter above have been published, including both original research and extensive reviews. However, they do not provide collected information on NIPU composites fabrication and processing. Hence, this review describes the latest progress in non-isocyanate polyurethane synthesis, modification, and finally processing. While focusing primarily on the carbonate/amine route, methods of obtaining NIPU are described, and their properties are presented. Ways of incorporating various compounds into NIPU matrices are characterized by the role of PHU materials in copolymeric materials or as an additive. Finally, diverse processing methods of non-isocyanate polyurethanes are presented, including electrospinning or 3D printing.

scholarly journals Destruxin A Interacts with Aminoacyl tRNA Synthases in Bombyx mori

2021 ◽  
Vol 7 (8) ◽  
pp. 593
Author(s):  
Jingjing Wang ◽  
Alexander Berestetskiy ◽  
Qiongbo Hu
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Bombyx Mori ◽  
Metarhizium Anisopliae ◽  
Free Amino ◽  
Molecular Target ◽  
Trna Synthetases ◽  
Interaction Mode ◽  
Aminoacyl Trna Synthetases ◽  
Wide Range

Destruxin A (DA), a hexa-cyclodepsipeptidic mycotoxin produced by the entomopathogenic fungus Metarhizium anisopliae, exhibits insecticidal activities in a wide range of pests and is known as an innate immunity inhibitor. However, its mechanism of action requires further investigation. In this research, the interactions of DA with the six aminoacyl tRNA synthetases (ARSs) of Bombyx mori, BmAlaRS, BmCysRS, BmMetRS, BmValRS, BmIleRS, and BmGluProRS, were analyzed. The six ARSs were expressed and purified. The BLI (biolayer interferometry) results indicated that DA binds these ARSs with the affinity indices (KD) of 10−4 to 10−5 M. The molecular docking suggested a similar interaction mode of DA with ARSs, whereby DA settled into a pocket through hydrogen bonds with Asn, Arg, His, Lys, and Tyr of ARSs. Furthermore, DA treatments decreased the contents of soluble protein and free amino acids in Bm12 cells, which suggested that DA impedes protein synthesis. Lastly, the ARSs in Bm12 cells were all downregulated by DA stress. This study sheds light on exploring and answering the molecular target of DA against target insects.

scholarly journals Impact of Foliar Application of Amino Acids on Total Phenols, Phenolic Acids Content of Different Mints Varieties under the Field Condition

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 599
Author(s):  
Živilė Tarasevičienė ◽  
Aloyzas Velička ◽  
Aurelija Paulauskienė
Keyword(s):  
Amino Acids ◽  
Phenolic Compounds ◽  
Phenolic Acids ◽  
Foliar Application ◽  
Mentha Piperita ◽  
Total Phenolic ◽  
Total Phenol Content ◽  
Individual Response ◽  
Total Phenols ◽  
Wide Range

Phenolic compounds have a number of benefits to human health and can be used as preventive compounds for the development of some chronic diseases. Mentha plants are not only a good source of essential oils, but also contain significant levels of wide range of phenolic compounds. The aim of this research was to investigate the possibility to increase phenols content in Mentha plants under the foliar application with L-phenylalanine, L-tryptophan, L-tyrosine at two concentrations (100 mg L−1 and 200 mg L−1) and to create preconditions for using this plant for even more diverse purposes. Quantitative and qualitative analyses of phenols in mints were performed by HPLC method. Foliar application of amino acids increased the total phenol content from 1.22 to 3.51 times depending on the treatment and mint variety. The most pronounced foliar application to total phenols content was tryptophane especially in Mentha piperita “Swiss”. Mentha piperita “Swiss” was affected most by foliar application and the amount of total phenolic acids depending on the treatment ranged from 159.25 to 664.03 mg 100 g−1 (DW), respectively, non-sprayed and sprayed with tryptophane 100 mg L−1. Our results suggest that the biophenol content varies according to such factors as foliar application and variety, and every single mint variety has individual response to different applications of amino acids.

Reactions of the radical cation derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) with amino acids. Kinetics and mechanism

2000 ◽  
Vol 78 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
C Aliaga ◽  
E A Lissi
Keyword(s):  
Amino Acids ◽  
Radical Cation ◽  
Sulfonic Acid ◽  
Biological Fluids ◽  
Reaction Rates ◽  
Kinetics And Mechanism ◽  
Specific Rate ◽  
Wide Range ◽  
Initial Ph ◽  
Secondary Reactions

Stable free radicals derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) have been extensively employed to monitor the antioxidant capacity of biological fluids and beverages. Besides reacting with typical antioxidants (such as phenols or thiols) these radicals react with a variety of hydrogen or electron donors. The present work reports on the kinetics and mechanism of these radical reactions with several amino acids. Reaction rates notably increase when the pH of the media increases and, when measured under similar conditions, follows the ordercysteine > > tryptophan > tyrosine > histidine > cystineThe kinetics of the process is interpreted in terms of a mechanism comprising an initial pH dependent reversible step, followed by secondary reactions of the substrate derived radical with itself or with another ABTS·+; this simple three-step mechanism leads to very complex kinetic expressions. The specific rate constants of several of the elementary steps were determined by working under a wide range of substrate, radical, and ABTS concentrations. The values obtained for the initial interaction between the ABTS derived radical and the substrate range from 0.5 M–1 s–1 to 1.9 × 106 M–1 s–1 for histidine and cysteine, respectively.Key words: ABTS radical cation, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), amino acids, kinetics.

scholarly journals Sorption Extraction of Rare Earth Metals from Wet-Process Phosphoric Acid

2021 ◽  
Vol 83 (1) ◽  
pp. 140-152
Author(s):  
Baltabekova Zhazira ◽  
Kenzhaliyev Bagdaulet ◽  
Lokhova Nina ◽  
Kassymzhanov Kaisar
Keyword(s):  
Rare Earth ◽  
Phosphoric Acid ◽  
Treatment Process ◽  
Cation Exchanger ◽  
Rare Earth Metals ◽  
Ion Exchangers ◽  
Technological Parameters ◽  
Complex Composition ◽  
Impurity Composition ◽  
Wet Process

When apatites and phosphorites are processed, up to 30% of rare earth metals are converted into wet-process phosphoric acid. Wet-process phosphoric acid from the phosphorite treatment process differs from apatite one by impurity composition, i.e. the iron content is by 3.5 times, and calcium is by 5.0 times more. The complex composition of the wet-process phosphoric acid from the phosphorite treatment process requires additional researches to select optimal ion exchangers and technological parameters of sorption. Various aspects of sorption have been studied to select the optimal ion exchangers and technological parameters, and technological modes for desorption of rare earth metals from a cation exchanger to obtain a concentrate of rare earth metals have been completed. The method enables to extract rare earth metals without changing the composition of commercial wet-process phosphoric acid directly in the production process of the enterprises engaged in the phosphorite treatment process.

scholarly journals Oxidative properties of carp red and white muscle

1989 ◽  
Vol 143 (1) ◽  
pp. 321-331 ◽  
Author(s):  
C. D. Moyes ◽  
L. T. Buck ◽  
P. W. Hochachka ◽  
R. K. Suarez
Keyword(s):  
Amino Acids ◽  
White Muscle ◽  
Citrate Synthase ◽  
Ketone Bodies ◽  
Redox Balance ◽  
Fatty Acyl ◽  
Oxidation Rates ◽  
Substrate Preferences ◽  
Glycerophosphate Dehydrogenase ◽  
Wide Range

Substrate preferences of isolated mitochondria and maximal enzyme activities were used to assess the oxidative capacities of red muscle (RM) and white muscle (WM) of carp (Cyprinus carpio). A 14-fold higher activity of citrate synthase (CS) in RM reflects the higher mitochondrial density in this tissue. RM mitochondria oxidize pyruvate and fatty acyl carnitines (8:O, 12:O, 16:O) at similarly high rates. WM mitochondria oxidize these fatty acyl carnitines at 35–70% the rate of pyruvate, depending on chain length. WM has only half the carnitine palmitoyl transferase/CS ratio of RM, but similar ratios of beta-hydroxyacyl CoA dehydrogenase/CS. Ketone bodies are poor substrates for mitochondria from both tissues. In both tissues mitochondrial alpha-glycerophosphate oxidation was minimal, and alpha-glycerophosphate dehydrogenase was present at low activities, suggesting the alpha-glycerophosphate shuttle is of minor significance in maintaining cytosolic redox balance in either tissue. The mitochondrial oxidation rates of other substrates relative to pyruvate are as follows: alpha-ketoglutarate 90% (RM and WM); glutamate 45% (WM) and 70% (RM); proline 20% (WM) and 45% (RM). Oxidation of neutral amino acids (serine, glycine, alanine, beta-alanine) was not consistently detectable. These data suggest that RM and WM differ in mitochondrial properties as well as mitochondrial abundance. Whereas RM mitochondria appear to be able to utilize a wide range of metabolic fuels (fatty acids, pyruvate, amino acids but not ketone bodies), WM mitochondria appear to be specialized to use pyruvate.

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