@article { ISI:000237126200040, title = {4-Formylazetidin-2-ones, synthon for the synthesis of (2R,3S) and (2S,3R)-3-amino-2-hydroxydecanoic acid (AHDA)}, journal = {Tetrahedron}, volume = {62}, number = {18}, year = {2006}, month = {MAY}, pages = {4615-4621}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient synthesis of 3-amino-2-hydroxydecanoic acid (AHDA), a nonproteinogenic amino acid, using enantiopure 3-benzyloxy-4-formylazetidin-2-one as a building block is described. Both the enantiomers of AHDA have been synthesized from the corresponding enantiomer of 3-benzyloxy-4-formylazetidin-2-one in good yield and optical purity. (c) 2006 Published by Elsevier Ltd.

}, keywords = {Amino acids, azetidin-2-ones, Staudinger reaction, stereoselective synthesis, Wittig reaction}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.01.082}, author = {Shirode, N. M. and Deshmukh, A. R. A. S.} } @article { ISI:000241179400014, title = {Hybrid foldamer with unique architecture from conformationally constrained aliphatic-aromatic amino acid conjugate}, journal = {Tetrahedron}, volume = {62}, number = {43}, year = {2006}, month = {OCT}, pages = {10141-10146}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

In this paper, we describe the design and synthesis of a novel hybrid foldamer, derived from a conformationally constrained aliphatic-aromatic amino acid conjugate that adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids from which the foldamer is composed. Conformational investigations confirmed the prevalence of a unique doubly bent conformation for the foldamer, in both solid and solution states, as evidenced from single crystal X-ray and 2D NOESY studies, respectively. The findings suggest that constrained aliphatic-aromatic amino acid conjugates offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures. Furthermore, the de novo design strategy disclosed herein has the potential for significantly augmenting the {\textquoteleft}tool-box{\textquoteright} of the modern day peptidominetic chemist, as well as providing a novel approach to the field of rational design. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {Amino acids, Conformation, Foldamer, Peptidomimetics}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.08.032}, author = {Srinivas, Deekonda and Gonnade, Rajesh G. and Ravindranathan, Sapna and Sanjayan, Gangadhar J.} } @article { ISI:000260776600007, title = {Functionalization of single-walled carbon nanotubes with azides derived from amino acids using click chemistry}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {8}, number = {7}, year = {2008}, month = {JUL}, pages = {3351-3356}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Single-walled carbon nanotubes (SWCNTs) were chemically functionalized with amino acid-based moieties. The covalent functionalization of alkyne-derived SWCNTs with well defined azides derived from amino acids was accomplished through Cu(I)-catalyzed Huisgen [3+2] dipolar cycloaddition click chemistry. Transmission electron microscopy, Raman spectroscopy, and infrared spectroscopic measurements confirmed the functionalization of SWCNTs by organic molecules derived from amino acids, and the resulting material showed some good solubility in the organic solvents such as tetrahydrofuran, CH2Cl2, and CHCl3.

}, keywords = {Amino acids, Carbon nanotubes, Click chemistry, Functionalization}, issn = {1533-4880}, doi = {10.1166/jnn.2008.109}, author = {Kumar, Indresh and Rana, Sravendra and Rode, Chandrashakher V. and Cho, Jae Whan} } @article { ISI:000261342600009, title = {Correlations of thermodynamic properties of aqueous amino acid-electrolyte mixtures}, journal = {Journal of Solution Chemistry}, volume = {38}, number = {1}, year = {2009}, month = {JAN}, pages = {95-114}, publisher = {SPRINGER/PLENUM PUBLISHERS}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Suitable equations have been proposed to correlate thermodynamic properties, like mean ion activity coefficients, volumes and compressibilities, of amino acids in electrolyte solutions. An amino acid-electrolyte-water interaction parameter is extracted from the regression of the amino acid property values in aqueous electrolyte solution that is then transferred to an expression to correlate the properties of the electrolyte in mixtures. The single interaction parameter can successfully correlate the published data on mean ion activity coefficients, apparent molar volumes and compressibilities of amino acids as well as of electrolytes in their aqueous mixtures. The equations are tested against the large number of experimental data sets available in the literature.

}, keywords = {Amino acids, Electrolytes, Pitzer equation, Thermodynamic properties}, issn = {0095-9782}, doi = {10.1007/s10953-008-9355-2}, author = {Saritha, C. and Satpute, Dilip B. and Badarayani, Rohini and Kumar, Anil} } @article { ISI:000279746300009, title = {Enantioselective synthesis of (+)-alpha-conhydrine and (-)-sedamine by L-proline-catalysed alpha-aminooxylation}, journal = {European Journal of Organic Chemistry}, number = {18}, year = {2010}, month = {JUN}, pages = {3437-3444}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

An efficient organocatalytic approach to the enantioslective synthesis of two important piperidine alkaloids, namely (+)-alpha-conhydrine (98\% ee) and (-)-sedamine (95\% ee), by L-proline-catalysed alpha-aminooxylation of aldehydes has been developed. The strategy involves an intramolecular cyclization to construct the piperidine core.

}, keywords = {alkaloids, Amino acids, Aminooxylation, Enantioselectivity, organocatalysis}, issn = {1434-193X}, doi = {10.1002/ejoc.201000169}, author = {Shaikh, Tanveer Mahamadali and Sudalai, Arumugam} } @article { ISI:000297737900020, title = {Synthesis and structural characterization of homochiral homo-oligomers of parent CIS- and trans-furanoid-beta-amino acids}, journal = {Chemistry-A European Journal}, volume = {17}, number = {46}, year = {2011}, month = {NOV}, pages = {12946-12954}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

The synthesis of homochiral homo-oligomers of cis- and trans-3-aminotetrahydrofuran-2-carboxylic acids (parent cis- and trans-furanoid-beta-amino acids, referred to as {\textquoteleft}{\textquoteleft}cis-/trans-FAA{\textquoteright}{\textquoteright}) has been carried out to understand their secondary structures and their dependence on the ring heteroatom. The oligomers of two diastereomers have been shown to have a distinct left-handed helicity. The cis-FAA homo-oligomers show a 14-helix structure, in contrast to the homo-oligomers of cis-ACPC, which adopt a sheet like structure. The trans-FAA homo-oligomers were found to adopt a 12-helix structure, the same trend found in trans-ACPC homo-oligomers. With the help of ab initio calculations, the structural features of cis-ACPC and cis-FAA hexamers were compared. We believe that the more compact packing of the cis-FAA hexapeptide should be due to a more favorable interaction between the ring and the backbone amide hydrogen.

}, keywords = {ab initio calculations, Amino acids, Density functional calculations, Peptides, secondary structures}, issn = {0947-6539}, doi = {10.1002/chem.201101855}, author = {Pandey, Sunil K. and Jogdand, Ganesh F. and Oliveira, Joao C. A. and Mata, Ricardo A. and Rajamohanan, Pattuparambil R. and Ramana, Chepuri V.} } @article { ISI:000304570000010, title = {Expanding the structural repertoire of beta/alpha Ant-Pro (anthranilic acid-proline) oligomers into gamma/alpha 2-Amb-Pro (2-aminomethyl benzoic acid-proline) oligomers}, journal = {Tetrahedron}, volume = {68}, number = {23}, year = {2012}, month = {JUN}, pages = {4399-4405}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

In this article, we report a novel class of heterogeneous synthetic oligomers featuring the conformationally constrained amino acid residues - 2-aminomethyl benzoic acid (2-Amb) and proline (Pro) in repeating sequences. Oligomers as large as hexadecamers featuring the conformationally restricted gamma/alpha 2-Amb-Pro motif have been assembled using solution-phase Boc strategy, following multi-step synthetic sequences starting from the commercially available O-toluic acid. EDC-mediated peptide coupling has been found to be optimum for the assembly of the relatively non-polar oligomers, which could be readily purified by the standard column chromatographic purification procedures. This study offers considerable prospects of expanding the structural repertoire of beta/alpha Ant-Pro motif, which has been described earlier to assume right-handed helical architecture displaying robust nine-membered-ring closed network of hydrogen-bonding interactions, into gamma/alpha 2-Amb-Pro motif. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Amino acids, Foldamer, Peptides, Proline, Synthetic oligomers}, issn = {0040-4020}, doi = {10.1016/j.tet.2012.02.006}, author = {Ramesh, Veera V. E. and Priya, Gowri and Rajamohanan, P. R. and Hofmann, Hans-Joerg and Sanjayan, Gangadhar J.} } @article { ISI:000303157400022, title = {Synthesis and structural characterization of homochiral homo-oligomers of cis-gamma-methoxy-substituted cis- and trans-furanoid-beta-amino acids}, journal = {European Journal of Organic Chemistry}, number = {13}, year = {2012}, month = {MAY}, pages = {2656-2663}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Herein we describe the synthesis of cis-/trans-3-aminotetrahydrofuran-2-carboxylic acids (cis-/trans-FAA) having a ?-methoxy group cis to the amine. The homo-oligomers of these two diastereomeric FAAs have been prepared. Preliminary investigation of their solution secondary structures revealed that they are the same as the homo-oligomers of the parent cis-/trans-FAA with the methoxy group only being a spectator substituent.

}, keywords = {Amino acids, helical structures, Oxygen heterocycles, Peptides}, issn = {1434-193X}, doi = {10.1002/ejoc.201101424}, author = {Giri, Awadut G. and Jogdand, Ganesh F. and Rajamohanan, Pattuparampil R. and Pandey, Sunil K. and Ramana, Chepuri V.} } @article { ISI:000322293300006, title = {Use of amino acids for a highly efficient somatic embryogenesis in grapevine {\textquoteleft}Crimson Seedless{\textquoteright}}, journal = {Vitis}, volume = {52}, number = {3}, year = {2013}, month = {JAN}, pages = {137-140}, publisher = {JKI-INSTITUT REBENZUCHTUNG}, address = {GEILWEILERHOF, D-76833 SIEBELDINGEN, GERMANY}, abstract = {

Somatic embryogenesis influenced by growth regulators and amino acids was studied in in vitro leaves of grapevine {\textquoteleft}Crimson Seedless{\textquoteright}. In vitro leaves of the cultivar were collected from multiple shoot cultures maintained on Murashige and Skoog{\textquoteright}s (MS) basal medium supplemented with 9 mu M N-6-benzyladenine (BA). Among the growth regulators used, BA at 4.5 mu M induced higher embryogenic response producing more number of somatic embryos per explant. This response was increased with the addition of 5 mu M naphthoxyl-acetic acid (NOA) to 1/2 MS containing 4.5 mu M BA. Further, supplementation of amino acids in the callus induction medium significantly improved the embryogenic response of in vitro leaves. The higher number of explants showing somatic embryo production (55.3 \%) and higher number of somatic embryos per explant (15.5 per explant) were recorded with the supplementation of 5 mM phenylalanine to callus induction medium. Primary somatic embryos showed repetitive embryogenesis on \% MS medium devoid of growth regulators. Plantlets derived from somatic embryos were transferred to soil-sand-peat mixture (1:1:1 v/v) and hardened plantlets were established in greenhouse with 90 \% survival. This somatic embryogenesis system has been successfully used for Agrobacterium-mediated transformation studies in {\textquoteleft}Crimson Seedless{\textquoteright} in our laboratory. To our knowledge, this is the first report on the use of amino acids for the high efficient somatic embryogenesis in grapevine.

}, keywords = {Amino acids, somatic embryogenesis, Vitis vinifera L., {\textquoteleft}Crimson Seedless{\textquoteright}}, issn = {0042-7500}, author = {Nookaraju, A. and Agrawal, Dinesh C.} } @article { ISI:000345826600002, title = {Heterogeneous foldamers from aliphatic-aromatic amino acid building blocks: current trends and future prospects}, journal = {European Journal of Organic Chemistry}, volume = {46}, number = {35}, year = {2014}, month = {DEC}, pages = {7763-7780}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Chemists{\textquoteright} constant pursuit of understanding of the underlying principles of nature{\textquoteright}s most intricate phenomenon such as protein folding has led to the development of the field of foldamers. The emergence of diverse classes of unnatural amino acid building blocks has unleashed countless opportunities to design, develop and explore the structural and functional aspects of synthetic peptides. One current trend in foldamer chemistry is the heterofoldamer approach, which involves systematic stoichiometric variation of various natural/unnatural amino acid residues, leading to conformational ordering with intriguing structural architectures. In this regard, the incorporation of aromatic amino acids provides efficient structural rigidification and tunability to the molecular scaffolds, which can exhibit a range of secondary structural features. Recent times have witnessed an upsurge of foldamers featuring aliphatic-aromatic residues with diverse structural propensities. This review is an effort to cover this rapidly developing field of foldamer science and also to envisage its future perspectives.

}, keywords = {Amino acids, Conformation analysis, Foldamers, hydrogen bonding, Peptides, Stacking interactions}, issn = {1434-193X}, doi = {10.1002/ejoc.201402877}, author = {Nair, Roshna V. and Vijayadas, Kuruppanthara N. and Roy, Arup and Sanjayan, Gangadhar J.} } @article { ISI:000340469800024, title = {Highly efficient chiral resolution of DL-arginine by cocrystal formation followed by recrystallization under preferential-enrichment conditions}, journal = {Chemistry-A European Journal}, volume = {20}, number = {33}, year = {2014}, month = {AUG}, pages = {10343-10350}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

An excellent chiral symmetry-breaking spontaneous enantiomeric resolution phenomenon, denoted preferential enrichment, was observed on recrystallization of the 1:1 cocrystal of dl-arginine and fumaric acid, which is classified as a racemic compound crystal with a high eutectic ee value (\>95\%), under non-equilibrium crystallization conditions. On the basis of temperature-controlled video microscopy and in situ time-resolved solid-state (CNMR)-C-13 spectroscopic studies on the crystallization process, a new mechanism of phase transition that can induce preferential enrichment is proposed.

}, keywords = {Amino acids, chiral resolution, cocrystals, Crystal growth, phase transitions}, issn = {0947-6539}, doi = {10.1002/chem.201402446}, author = {Iwama, Sekai and Kuyama, Kazunori and Mori, Yuko and Manoj, Kochunnoonny and Gonnade, Rajesh G. and Suzuki, Katsuaki and Hughes, Colan E. and Williams, P. Andrew and Harris, Kenneth D. M. and Veesler, Stephane and Takahashi, Hiroki and Tsue, Hirohito and Tamura, Rui} } @article {46957, title = {Towards in situ continuous feeding via controlled release of complete nutrients for fed-batch culture of animal cells}, journal = {Biochemical Engineering Journal}, volume = {154}, year = {2020}, month = {FEB }, pages = {107436}, type = {Article}, abstract = {

Small-scale culture of animal cells in suspension is of importance for many applications. At a small-scale, fed-batch is achieved either by manual bolus feeding or the use of liquid handling robots. In this study, we report an alternate application of a hydrogel for in situ continuous delivery of a nutrient feed comprising 18 amino acids, vitamins, antioxidants, and trace elements. We show that amino acid release is sustained for at least seven days. Importantly, release rates of individual amino acids can be independently modulated by changing their loading. We demonstrate the application of this hydrogel for complete in situ feeding of nutrients to a suspension adapted CHO cell line expressing IgG leading to 2.7-fold and 4-fold improvement in integral viable cell density (IVCD) and volumetric productivity respectively. This is similar to improvements obtained by bolus liquid feeding. Further, supplying glucose from the same hydrogel to eliminate manual feeding led to a 1.8-fold increase in IVCD accompanied by a 3-fold increase in volumetric productivity as compared to batch culture. In summary, this study provides a proof-of-concept that hydrogels can enable completely closed in situ feeding for mammalian cell culture requiring no external intervention. Such continuous in situ delivery can potentially enable closed culture systems maintaining nutrients at low levels mimicking physiological concentrations.

}, keywords = {Amino acids, CHO cells, Closed system, Fed-batch, Hydrogel for continuous feeding, In situ nutrient release}, issn = {1369-703X}, doi = {10.1016/j.bej.2019.107436}, author = {Rawat, Jyoti and Gadgil, Mugdha} } @article {48026, title = {Choline-amino acid-derived bio-ionic liquids for solubility enhancement of zafirlukast}, journal = {AAPS Pharmscitech}, volume = {23}, year = {2022}, month = {MAY}, pages = {146}, type = {Article}, abstract = {

This study investigated the application of bio-ionic liquids (ILs) prepared from choline as cation and amino acid as anion for solubility enhancement of poorly water-soluble drug, Zafirlukast (ZFL). Herein, the solubility of ZFL in water and mixtures of water and ILs was assessed using UV spectroscopy at two temperature points 25 degrees C and 37 degrees C with increasing concentrations of IL. ZFL solubility was found to improve linearly with increasing concentration of [Ch][Pro] in water, representing 35- to 37-fold improvement in ZFL solubility at maximum concentration of [Ch][Pro] (1\% w/v) compared to when only pure water was present. Also, the effect of IL on ZFL solubility was analyzed using NMR, DSC, and TGA. These results clearly suggest that ZFL solubility was increased by forming hydrogen bonds with selected [Ch][Pro] IL. Toxicity study of ILs was tested against gram-positive and gram-negative bacteria. Since IL solvent was found to increase the solubility of ZFL, this may serve as {\textquoteleft}{\textquoteleft}functional excipient solvent{\textquoteright}{\textquoteright} for solubility enhancement in its commercialized formulations.

}, keywords = {Amino acids, choline chloride, Ionic liquid, solubility, zafirlukast}, issn = {1530-9932}, doi = {10.1208/s12249-022-02296-8}, author = {Gaikwad, Namrata and Kudal, Swapna and Avachat, Amelia M.} } @article {48439, title = {Amino acid abundance and composition in cell culture medium affects trace metal tolerance and cholesterol synthesis}, journal = {Biotechnology Progress}, volume = {39}, year = {2023}, month = {JAN}, type = {Article}, abstract = {

Amino acid compositions of cell culture media are empirically designed to enhance cell growth and productivity and vary both across media formulations and over the course of culture due to imbalance in supply and consumption. The interconnected nature of the amino acid transporters and metabolism suggests that changes in amino acid composition can affect cell physiology. In this study, we explore the effect of a step change in amino acid composition from a DMEM: F12-based medium to a formulation varying in relative abundances of all amino acids, evaluated at two amino acid concentrations (lean LAA vs. rich HAA). Cell growth was inhibited in LAA but not HAA. In addition to the expected effects on expression of the cell cycle, amino acid response and mTOR pathway genes in LAA, we observed an unanticipated effect on zinc uptake and efflux genes. This was accompanied by a lower tolerance to zinc supplementation in LAA but not in the other formulations. Histidine was sufficient but not necessary to prevent such zinc toxicity. Additionally, an unanticipated downregulation of genes in the cholesterol synthesis pathway was observed in HAA, accompanied by an increase in cellular cholesterol content, which may depend on the relative abundances of glutamine and other amino acids. This study shows that changes in the amino acid composition without any evident effect on growth may have profound effects on metabolism. Such analyses can help rationalize the designing of medium and feed formulations for bioprocess applications beyond replenishment of consumed components.

}, keywords = {Amino acids, cell culture medium, CHO cells, Cholesterol, zinc}, issn = {8756-7938}, doi = {10.1002/btpr.3298}, author = {Rawat, Jyoti and Bhambri, Aksheev and Pandey, Ujjiti and Banerjee, Sanchita and Pillai, Beena and Gadgil, Mugdha} }