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A new form of Scatchard plot to study binding of fluoride ion on urease by isothermal titration calorimetry

2013-07-17T16:37:33Z

Title: A new form of Scatchard plot to study binding of fluoride ion on urease by isothermal titration calorimetry Authors: Saboury, A A Abstract: A new equation with a useful simple graphical method, very similar to the Scatchard plot was introduced to obtain the equilibrium constant and the enthalpy of binding using isothermal titration calorimetric data. On applying this simple graphical method to study the binding of fluoride ion on jack bean urease, the dissociation equilibrium constant obtained was remarkably consistent with the inhibition constant obtained from assay of enzyme activity in the presence of fluoride ion. Page(s): 347-350

Adsorption of glycine and alanine on montmorillonite with or without coordinated divalent cations

2013-07-18T16:38:55Z

Title: Adsorption of glycine and alanine on montmorillonite with or without coordinated divalent cations Authors: Kalra, Sippy; Pant, C K; Pathak, H D; Mehta, M S Abstract: Adsorption of glycine and alanine on montmorillonite and on Ca²⁺- and Mg²⁺- exchanged montmorillonite clay over a range of pH (4.0-9.0) and temperature (20-35^oC) under possible abiotic conditions have been investigated UV-spectrophotometrically. Adsorption of both the amino acids was considerable on all the three adsorbents used. Maximum adsorption was observed at 25^o C and neutral pH. Ca²⁺-montmorillonite exhibited relatively better adsorption as compared to Mg²⁺-exchanged form or montmorillonite. The values of K_L and X_m were determined using Langmuir isotherm characteristics. Page(s): 341-346

X -band EPR spectra of copper(II)-dipeptide-imlidazole (1:1:0/1) system

2016-07-20T05:10:42Z

Title: X -band EPR spectra of copper(II)-dipeptide-imlidazole (1:1:0/1) system Authors: Patel, R N; Pandeya, K B Abstract: The electron paramagnetic resonance (EPR) spectra of copper(II)-GA/GV and copper(II)-GA/GV-imH/eimH/ m-imH have been recorded as a function of pH. Imidazole enters coordination at pH ~ 7.0, whereas the substituted imidazoles do so at pH> 7.0. The σ-bonding appears to have a moderate degree of covalency. In-plane and out-of-plane π-bonding has been found to be more strongly covalent. Page(s): 334-340

Synthesis, conformation and vibrational dynamics of apolipoprotein B fragment, -Asn-Cys-Lys-Val-Glu-Leu-

2016-07-20T05:01:39Z

Title: Synthesis, conformation and vibrational dynamics of apolipoprotein B fragment, -Asn-Cys-Lys-Val-Glu-Leu- Authors: Srivastava, Seema; Melkani, Girish Chandra; Singh, Shyam; Gupta, Vishwambhar Dayal Abstract: It is assumed that all biological processes are dynamical in nature and the low frequency collective modes, particularly the skeletal modes arising from the main chain and the side chain play an important role in such processes. To identify these a complete normal mode analysis of the hexapeptide -Asn-Cys-Lys-Yal-Glu-Leu-, a fragment of apolipoprotein B has been carried out. The assignment of modes is greatly assisted by similar studies on the tetra -Cys-Lys-Val-Glu- and tripeptides (-Asn-Cys-Lys-, -Yal-Glu-Leu-) fragments of the hexapeptide. All the four peptides have been synthesized by the solid phase peptide method using 9-flurrenyl methyloxycarbonyl (Fmoc) on 4-methyl benzhyldrylamine (MBHA) and Wang's resins. Their conformation is determined from the Ramachandran Maps which are based on the global energy minimization method. It is supported by the propensity parameters for the amino acids. Page(s): 318-333