scholarly journals Entropy Effects in Intermolecular Associations of Crown-Ethers and Cyclodextrins with Amino Acids in Aqueous and in Non-Aqueous Media

Entropy ◽  
2021 ◽  
Vol 24 (1) ◽  
pp. 24
Author(s):  
Tatyana Usacheva ◽  
Irina Terekhova ◽  
Diana Alister ◽  
Mikhail Agafonov ◽  
Natalya Kuranova ◽  
...  
Keyword(s):  
Amino Acids ◽  
Crown Ethers ◽  
Driving Forces ◽  
Aqueous Media ◽  
Thermodynamic Characteristics ◽  
Structural Features ◽  
Organic Mixtures ◽  
Molecular Complexation ◽  
Thermodynamics Of Complex Formation ◽  
Entropy Effects

The analysis of the ratios of entropy and enthalpy characteristics and their contributions to the change in the Gibbs energy of intermolecular interactions of crown ethers and cyclodextrins with amino acids is carried out. Two different types of macrocycles were chosen for examination: crown ethers with a hydrophilic interior and cyclodextrins with a hydrophobic inner cavity and a hydrophilic exterior. The thermodynamics of complex formation of crown ethers and cyclodextrins with amino acids in water and aqueous-organic solvents of variable composition was examined. The contributions of the entropy solvation of complexes of 18-crown-6 with glycine, alanine, phenylalanine to the change in the entropy of complexation in water-ethanol and water-dimethyl sulfoxide solvents was calculated and analyzed. It was found that the ratios of the entropy and enthalpy solvation of the reagents for these systems have similar trends when moving from water to aqueous-organic mixtures. The relationship between the thermodynamic characteristics and structural features of the complexation processes between cyclodextrins and amino acids has been established. The thermodynamic enthalpy–entropy compensation effect was revealed, and its features for complexation of cyclodextrins and 18-crown-6 were considered. It was concluded that, based on the thermodynamic parameters of molecular complexation, one could judge the mode of the formation of complexes, the main driving forces of the interactions, and the degree of desolvation.

scholarly journals Alum Catalyzed Simple, Efficient, and Green Synthesis of 2-[3-Amino-5-methyl-5-(pyridin-3-yl)-1,5-dihydro-4H-1,2,4-triazol-4-yl]propanoic Acid Derivatives in Aqueous Media

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Harshita Sachdeva ◽  
Diksha Dwivedi ◽  
Rekha Saroj
Keyword(s):  
Amino Acids ◽  
Green Chemistry ◽  
Green Synthesis ◽  
Aqueous Media ◽  
Propanoic Acid ◽  
Ft Ir ◽  
C Nmr

Alum (KAl(SO4)2·12H2O) is an inexpensive, efficient, and nontoxic catalyst used for the synthesis of 2-[3-amino-5-methyl-5-(pyridin-3-yl)-1,5-dihydro-4H-1,2,4-triazol-4-yl]propanoic acid derivatives in aqueous media by the reaction of 3-acetyl pyridine(1), amino acids(2)/(6), and thiosemicarbazide(4)at 80°C. This methodology offers significant improvements for the synthesis of products with regards to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts which uphold the motto of green chemistry. Synthesized compounds have been characterized by FT-IR,13C NMR, and1HNMR spectroscopy.

MATHEMATICAL MODELS FOR THE SYNTHESIS OF PLANT-BASED COMPOSITIONS WITH IMPROVED AMINO ACID COMPOSITION

2021 ◽  
Author(s):  
Irina Gaivoronskaya ◽  
Valenitna Kolpakova
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mathematical Models ◽  
Functional Properties ◽  
Amino Nitrogen ◽  
Essential Amino Acids ◽  
Major Allergen ◽  
Structural Features ◽  
Covalent Bonds ◽  
Pea Protein

The aim of the work was to optimize the process of obtaining multicomponent protein compositions with high biological value and higher functional properties than the original vegetable protein products. Was realized studies to obtain biocomposites on the base of pea protein-oat protein and pea protein-rice protein. Developed composites were enriched with all limited amino acids. For each of the essential amino acids, the amino acid score was 100% and higher. Protein products used in these compositions are not in major allergen list, which allows to use these compositions in allergen-free products and specialized nutrition. To determine biosynthesis parameters for compositions from pea protein and various protein concentrates with the use of transglutaminase enzyme, was studied effect of concentration and exposition time on the amount of amino nitrogen released during the reaction. Decreasing of amino nitrogen in the medium indicated the occurrence of a protein synthesis reaction with the formation of new covalent bonds. Were determined optimal parameters of reaction: the hydromodule, the exposure time, the concentration of EP of the preparation, were obtained mathematical models. Studies on the functional properties of composites, the physicochemical properties of the proteins that make up their composition, and structural features will make it possible to determine the uses in the manufacture of food products based on their ability to bind fat, water, form foam, gels, and etc.

Isolation and characterization of some novel genes of the apolipoprotein A-I family in Japanese eel, Anguilla japonica

2011 ◽  
Vol 6 (4) ◽  
pp. 545-557 ◽  
Author(s):  
Malay Choudhury ◽  
Takahiro Oku ◽  
Shoji Yamada ◽  
Masaharu Komatsu ◽  
Keita Kudoh ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Consensus Sequence ◽  
Structural Features ◽  
Lipid Binding ◽  
Japanese Eel ◽  
Amino Acid Sequences ◽  
Novel Genes ◽  
Isolation And Characterization

AbstractApolipoproteins such as apolipoprotein (apo) A-I, apoA-IV, and apoE are lipid binding proteins synthesized mainly in the liver and the intestine and play an important role in the transfer of exogenous or endogenous lipids through the circulatory system. To investigate the mechanism of lipid transport in fish, we have isolated some novel genes of the apoA-I family, apoIA-I (apoA-I isoform) 1–11, from Japanese eel by PCR amplification. Some of the isolated genes of apoIA-I corresponded to 28kDa-1 cDNAs which had already been deposited into the database and encoded an apolipoprotein with molecular weight of 28 kDa in the LDL, whereas others seemed to be novel genes. The structural organization of all apoIA-Is consisted of four exons separated by three introns. ApoIA-I10 had a total length of 3232 bp, whereas other genes except for apoIA-I9 ranged from 1280 to 1441 bp. The sequences of apoIA-Is at the exon-intron junctions were mostly consistent with the consensus sequence (GT/AG) at exon-intron boundaries, whereas the sequences of 3′ splice acceptor in intron 1 of apoIA-I1-7 were (AC) but not (AG). The deduced amino acid sequences of all apoIA-Is contained a putative signal peptide and a propeptide of 17 and 5 amino acid residues, respectively. The mature proteins of apoIA-I1-3, 7, and 8 consisted of 237 amino acids, whereas those of apoIA-I4-6 consisted of 239 amino acids. The mature apoIA-I10 sequence showed 65% identity to amino acid sequence of apoIA-I11 which was associated with an apolipoprotein with molecular weight of 23 kDa in the VLDL. All these mature apoIA-I sequences satisfied the common structural features depicted for the exchangeable apolipoproteins such as apoA-I, apoA-IV, and apoE but apoIA-I11 lacked internal repeats 7, 8, and 9 when compared with other members of apoA-I family. Phylogenetic analysis showed that these novel apoIA-Is isolated from Japanese eel were much closer to apoA-I than apoA-IV and apoE, suggesting new members of the apoA-I family.

Molecular cloning of cDNAs encoding two types of gonadotrophin α subunit from the masu salmon, Oncorhynchus masou: construction of specific oligonucleotides for the α1 and α2 subunits

1993 ◽  
Vol 11 (3) ◽  
pp. 265-273 ◽  
Author(s):  
K Gen ◽  
O Maruyama ◽  
T Kato ◽  
K Tomizawa ◽  
K Wakabayashi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Structural Difference ◽  
Structural Features ◽  
Masu Salmon ◽  
Time Interval ◽  
Oncorhynchus Masou ◽  
Α Subunit ◽  
Polymerase Chain ◽  
Fossil Records ◽  
Masu Salmon Oncorhynchus Masou

ABSTRACT Two types of cDNA (GTHα1 and -α2) encoding the α subunits of masu salmon (Oncorhynchus masou) gonadotrophin were cloned by the reverse transcription-polymerase chain reaction for pituitary mRNAs. The nucleotide sequences showed that the GTHα1 cDNA was 380 bp long, encoding 119 amino acids, and that GTHα2 cDNA was 365 bp long, encoding 114 amino acids. The masu salmon α subunit types had a few differences between the sequences, with homologies of 80% (nucleotide sequence) and 72% (amino acid sequence). The structural difference between the α1 and α2 subunits was predicted using hydropathic analysis. The evolutionary interval between masu and chum salmon was estimated to be 4·0 and 2·3 million years by comparing their GTHα1 and -α2 subunits respectively. These time values are roughly consistent with the evolutionary time interval (3·0 million years) estimated from fossil records and an isozyme study. Specific synthetic oligonucleotide probes were constructed and used for genomic Southern blot analyses. The restriction fragment sizes of the GTHα1 and -α2 genes were similar, and when their patterns were compared with those from four other teleosts, each species showed a different pattern from the others, but no difference between their respective α1 and α2 genes. Therefore, the structural features of the GTHα1 and -α2 genes may have diverged in a similar manner in these five teleosts.

Zinc-mediated carbon radical addition to glyoxylic imines in aqueous media for the synthesis of α-amino acids

2005 ◽  
Vol 3 (6) ◽  
pp. 1124-1128 ◽  
Author(s):  
Masafumi Ueda ◽  
Hideto Miyabe ◽  
Hisako Sugino ◽  
Takeaki Naito
Keyword(s):  
Amino Acids ◽  
Aqueous Media ◽  
Radical Addition

scholarly journals Structural basis for divergent and convergent evolution of catalytic machineries in plant aromatic amino acid decarboxylase proteins

2020 ◽  
Vol 117 (20) ◽  
pp. 10806-10817 ◽  
Author(s):  
Michael P. Torrens-Spence ◽  
Ying-Chih Chiang ◽  
Tyler Smith ◽  
Maria A. Vicent ◽  
Yi Wang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Convergent Evolution ◽  
Structural Features ◽  
Divergent Evolution ◽  
Structural Basis ◽  
Acid Decarboxylase ◽  
Substrate Selectivity ◽  
Amino Acid Decarboxylase ◽  
Catalytic Mechanisms

Radiation of the plant pyridoxal 5′-phosphate (PLP)-dependent aromatic l-amino acid decarboxylase (AAAD) family has yielded an array of paralogous enzymes exhibiting divergent substrate preferences and catalytic mechanisms. Plant AAADs catalyze either the decarboxylation or decarboxylation-dependent oxidative deamination of aromatic l-amino acids to produce aromatic monoamines or aromatic acetaldehydes, respectively. These compounds serve as key precursors for the biosynthesis of several important classes of plant natural products, including indole alkaloids, benzylisoquinoline alkaloids, hydroxycinnamic acid amides, phenylacetaldehyde-derived floral volatiles, and tyrosol derivatives. Here, we present the crystal structures of four functionally distinct plant AAAD paralogs. Through structural and functional analyses, we identify variable structural features of the substrate-binding pocket that underlie the divergent evolution of substrate selectivity toward indole, phenyl, or hydroxyphenyl amino acids in plant AAADs. Moreover, we describe two mechanistic classes of independently arising mutations in AAAD paralogs leading to the convergent evolution of the derived aldehyde synthase activity. Applying knowledge learned from this study, we successfully engineered a shortened benzylisoquinoline alkaloid pathway to produce (S)-norcoclaurine in yeast. This work highlights the pliability of the AAAD fold that allows change of substrate selectivity and access to alternative catalytic mechanisms with only a few mutations.

scholarly journals Synthesis, Molecular Recognition Study and Liquid Membrane-Based Applications of Highly Lipophilic Enantiopure Acridino-Crown Ethers

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2571
Author(s):  
Ádám Golcs ◽  
Bálint Árpád Ádám ◽  
Viola Horváth ◽  
Tünde Tóth ◽  
Péter Huszthy
Keyword(s):  
Crown Ethers ◽  
Liquid Membrane ◽  
Structural Features ◽  
Amino Acid Derivatives ◽  
Electrochemical Studies ◽  
Model Compounds ◽  
Guest Molecules ◽  
Enantiomeric Recognition ◽  
Sensor Molecules ◽  
Phase Transport

New highly lipophilic enantiopure crown ethers containing a heterocyclic unit have been synthesized. Phase transport, UV-Vis- and fluorescence spectrophotometric investigations as well as electrochemical studies on the complexation of the new macrocycles with several amine and amino acid derivatives were also carried out. Achiral amines were used for studying the structural preference of the new macrocycles. Among the studied structural features of the guest molecules, the intermolecular π-π interaction showed the most significant effect on complexation, which made the aralkylamine-type compounds the most preferable guest molecules. The studied liquid membrane-based applications and photophysical investigations showed appreciable enantiomeric recognition toward some aralkylamine model compounds with homochiral preferences. New crown ether derivatives (R,R)-2 and (S,S)-2 were successfully applied as enantioselective carrier and sensor molecules.

Selective O-functionalization of phenolic α-amino acids with crown ethers bearing cyclophosphazene sub-units

Tetrahedron ◽  
2011 ◽  
Vol 67 (11) ◽  
pp. 2096-2102 ◽  
Author(s):  
Michele Penso ◽  
Angelamaria Maia ◽  
Vittoria Lupi ◽  
Giovanni Tricarico
Keyword(s):  
Amino Acids ◽  
Crown Ethers
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