Faculty Publications

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Subject: search.filters.subject.Amino acids

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Now showing 1 - 10 of 27
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    Fast and efficient synthesis of N-substituted ?-aminobutyric acids by grinding at room temperature
    (Springer Verlag, 2013) Bhat, S.I.; Trivedi, D.R.
    Green chemistry is gaining increasing interest due to the growing awareness of the chemical community for sustainable development. Green chemistry solutions include synthesis without solvent and catalyst because many solvents and catalysts are toxic and expensive. Herein, we report the solvent and catalyst free method for the synthesis of N-substituted derivatives of ?-aminobutyric acid by direct aza-Michael addition of amines to crotonic acid. The protocol involves simple mixing or grinding the reactants at room temperature. The ?-amino acid derivatives were obtained in 82-100 % yield with a short reaction time without any tedious workup procedures. Our findings thus reveal a promising alternative to previously used procedures. © 2013 Springer-Verlag Berlin Heidelberg.
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    Molecular docking studies of some new imidazole derivatives for antimicrobial properties
    (2013) Vijesh, A.M.; Isloor, A.M.; Telkar, S.; Arulmoli, T.; Fun, H.-K.
    In modern drug designing, molecular docking is routinely used for understanding drug-receptor interaction. In the present study six imidazole derivatives containing substituted pyrazole moiety (2a,. b and 4a-d) were synthesized. Structures of the newly synthesized compounds were characterized by spectral studies. Compounds were screened for their antibacterial activity. Compound 4c was found to be potent antimicrobial against Pseudomonas aeruginosa at concentrations of 1 and 0.5. mg/mL compared to standard drug Streptomycin. All the compounds were subjected to molecular docking studies for the inhibition of the enzyme l-glutamine: d-fructose-6-phosphate amidotransferase [GlcN-6-P] (EC 2.6.1.16). The in silico molecular docking study results showed that, all the synthesized compounds having minimum binding energy and have good affinity toward the active pocket, thus, they may be considered as good inhibitor of GlcN-6-P synthase. © 2011.
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    Synthesis and antimicrobial activities of some novel 1,2,4-triazole derivatives
    (2013) Mange, Y.J.; Isloor, A.M.; Malladi, S.; Isloor, S.; Fun, H.-K.
    In the present investigation, a series of new Schiff bases 4a-f were synthesized by the condensation of N-[(4-amino-5-sulfanyl-4. H-1,2,4-triazol-3-yl)methyl]-4-substituted-benzamides 3a-b with various substituted aromatic aldehydes in ethanol-dioxane mixture using catalytic amount of sulfuric acid. The starting materials 3a-b were in turn synthesized by the fusion of benzoyl glycine/substituted benzoylglycine with thiocarbohydrazide. Newly synthesized compounds were characterized by IR, NMR, mass spectra and elemental analyses. All the compounds were evaluated for their antibacterial and antifungal activity using the Minimum Inhibition Concentration (MIC) method by serial dilution technique. Few of the compounds were found to be biologically active. © 2011.
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    Partial molar volume and partial molar isentropic compressibility study of glycine betaine in aqueous and aqueous KCl or MgCl2 solutions at temperatures T = 288.15-318.15 K
    (2013) Karanth, V.R.; Bhat, D.K.
    Partial molar volume, ?v0, isentropic compressibility, ?s, and partial molar isentropic compressibility, ?k0 of glycine betaine in aqueous and aqueous KCl or MgCl2 solutions have been computed using the experimental density and speed of sound data at temperatures, T = 288.15-318.15 K. The transfer partial molar volumes, ?tr?v0, and transfer partial molar isentropic compressibilities, ?tr?k0, have also been evaluated using the experimental data. The partial molar volumes of glycine betaine were computed using the usual equation as well as the equation employed by Pitkänen et al. So obtained values have been compared with literature values. The variations in experimental and computed parameters have been discussed in terms of solute-solvent and solute-solute interactions. © 2013 Elsevier B.V. All rights reserved.
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    Partial molar volumes and compressibilities of glycine betaine in aqueous NaCl solutions at temperatures T=(288.15-318.15)K
    (Elsevier, 2014) Karanth, V.R.; Bhat, D.
    The partial molar volumes, partial molar isentropic compressibilities, transfer molar volumes and transfer molar isentropic compressibilities of the system: glycine betaine in aqueous (0.1, 0.2, 0.3, 0.4 and 0.5molkg-1) NaCl solutions at different temperatures were determined using the experimental values of density and speed of sound. The positive transfer molar volumes of the systems indicated the presence of strong solute-solvent interactions. The electrostatic charge-charge interactions (among Na+/Cl- ions and amino/carboxylic groups of glycine betaine) were found to be predominant over the ionic-hydrophobic interactions (among Na+/Cl- ions and CH2/CH3 groups of the glycine betaine) in aqueous solutions. Size of the metal ion was found to influence the volumetric properties to an appreciable extent. © 2014 Elsevier B.V.
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    New D-?-A type indole based chromogens for DSSC: Design, synthesis and performance studies
    (Elsevier Ltd, 2015) Babu, D.D.; Gachumale, S.R.; Anandan, S.; Vasudeva Adhikari, A.V.
    Three new Donor-?-Acceptor type dyes D1-3 carrying 3-(1-hexyl-1H-indol-3-yl)-2-(thiophen-2-yl)acrylonitrile as backbone with three different acceptor units were designed and synthesized as promising sensitizers for solar cell application. The new dyes were characterized using various spectral and elemental analyses. Their optical and electrochemical properties were investigated using spectrophotometry and cyclic voltammetry respectively, while their photovoltaic performance was evaluated by a device fabrication study. The devices were subjected to electrochemical impedance spectroscopy to gain an insight into the interfacial charge transfer and recombination process while in use. Further, density functional theory study was carried out to investigate their Frontier Molecular Orbital energy states. The study reveals that the dye carrying 4-aminobenzoic acid as an acceptor showed the highest photovoltaic efficiency among the three dyes. This can be attributed to the longer electron lifetime and lower recombination rates. Additionally, a Single crystal X-ray diffraction study confirmed the structure of a key intermediate. © 2014 Elsevier Ltd. All rights reserved.
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    Partial purification and characterization of L-asparaginase from an endophytic Talaromyces pinophilus isolated from the rhizomes of Curcuma amada
    (Elsevier, 2016) Krishnapura, P.R.; Belur, P.D.
    l-Asparaginase is a commercially significant enzyme. There exists a demand for a broad variety of microbial l-asparaginases with characteristics compatible with its different applications. Endophytic microorganisms, in particular are emerging as potential sources of l-asparaginases. The current work involves partial purification and characterization of l-asparaginase from Talaromyces pinophilus, an endophytic fungus isolated from the rhizomes of Curcuma amada. Maximum enzyme activity could be achieved at pH 8.0 and with temperature 28 °C. The enzyme Exhibits 95 % and 98% of its total activity at physiological pH and temperature, respectively. The enzyme activity is largely unhindered in the presence of metal ions such as Ca2+, Cu2+, Fe2+, Mg2+, Mn2+, Zn2+. Increase in the enzyme activity in the presence of thiol groups and reduction in the same upon addition of thiol blockers indicates the involvement of cysteine in the enzyme's catalytic activity. The enzyme is a heterodimer of 62 kDa and 39 kDa. The enzyme has a Km of 6.4 mM, its turnover number towards l-asparagine is 286.3 s-1. The enzyme has 16% glutaminase activity; its Km towards glutamine is 13.3 mM and turnover number is 54.6 s-1. Our results highlight that l-asparaginase from endophytic Talaromyces pinophilus could be considered as potential candidate for clinical and industrial trials, owing to its efficiency and biochemical properties. To the best of our knowledge, this is the first report on partial purification and characterization of L-asparaginase from an endophyte. © 2015 Elsevier B.V. All rights reserved.
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    Retention of high dielectric constant sodium beta alumina via solution combustion: Role of aluminum ions complexation with fuel
    (Elsevier Ltd, 2018) Gupta, B.; Pujar, P.; Mal, S.S.; Gupta, D.; Mandal, S.
    In the present study, solution combustion technique has been explored to synthesize Sodium ?-alumina (SBA; NaAl11O17) powder and thin films. Three fuels namely urea, glycine and citric acid have been used to seek the feasibility of synthesizing crystalline SBA powder at low temperature. Also, the effect of nature of fuels used as well as calcination treatment on phase evolution and morphology of the as-combusted powder was investigated. Thermal analysis and X-ray diffraction studies suggest the formation of crystalline SBA powder at temperature as low as 259 °C, using urea in the combustion reaction whereas other fuels resulted in amorphous SBA phase and this variation in phase was found due to difference in exothermicity of the fuel used. Thermodynamic and spectroscopic analyses showed that the exothermicity of fuel depends on various factors like (i) standard heat of formation of fuel and (ii) the complexation offered by fuel to metal cations. Furthermore, sodium ?-alumina thin film capacitor (metal-insulator-metal) was also fabricated using urea via spray combustion synthesis. The sodium ?-alumina thin film showed a high dielectric value (?r) of ~21. © 2017 Elsevier Ltd and Techna Group S.r.l.
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    Improving the catalytic efficiency of Fibrinolytic enzyme from Serratia marcescens subsp. sakuensis by chemical modification
    (Elsevier Ltd, 2018) Krishnamurthy, A.; Mundra, S.; Belur, P.D.
    Microbial fibrinolytic enzymes have gained increased attention due to their potential to prevent or cure cardiovascular diseases. Promising natural enzymes are often modified to improve/enhance the kinetic constants. Hence an attempt was made to chemically modify the fibrinolytic enzyme produced by marine Serratia marcescens subsp. sakuensis using amino acid specific modifiers. The aim was to enhance the kinetic constants and gather information on the vital amino acid residues involved in the catalysis. Modification of cysteine, histidine, tryptophan and serine residues resulted in drastic reduction in fibrinolytic activity indicating their presence in the active site. Modification of carboxylate residues resulted in a 19-fold increase in specific activity suggesting their presence in the catalytic site. Interestingly, ratio of fibrinolytic to fibrinogenolytic activity of the modified enzyme did not change significantly. There was a 507-fold reduction in Km value after chemical modification and due to that, 219-fold enhancement of catalytic efficiency was evidenced. Circular dichroism spectrum analysis of the modified and native enzyme revealed changes in ?- helix and ß-sheet conformation of the enzyme. Furthermore, the modified enzyme was more responsive to the presence of most of the metal ions tested. © 2018 Elsevier Ltd