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    Öğe
    Investigation of the Hydration of Bovine Serum Albumin by an NMR Titration Method
    (Asian Journal Of Chemistry, 2010) Kavak, Gulten; Yilmaz, Ali; Morris, Gareth; Heatley, Frank
    In this study, NMR titration method was used to determine the dynamics of hydration water. Solutions were made by dehydration procedures and relaxation measurements were carried out on a Vnmr (Varian NMR) spectrometer operating at 300 MHz for proton and relaxation rates (Irri) were plotted versus M(s)/M(w). It was seen that the NMR titration data was separated into 2 line segments. The intercepts of the first line segment with lower mass of solute/mass of water (M(s)/M(w)) ratio and the second line segment with higher M(s)/M(w), are 2.15 and 2,57, respectively. The correlation times for free and structured water were obtained as 5.56 x 10(-12) S and 1.5 x 10(-11) s, respectively. The 1/T(1) and 1/T(2) relaxation rates increase as the protein concentration increases. This implies that the protein is reducing the motion of water molecules. The correlation times (tau(c)) were calculated by using the experimental data and relaxation theory related. These results suggest that the relaxation times of water layers surrounding a protein could be determined by T, measured versus M(p)/M(w). Present results were correlated well with the results from other measurements techniques. The data also suggest that the relaxation mechanism of bovine serum albumin (or serum proteins) can be explained in terms of fast chemical exchange of protons between bulk water and water bound to proteins.
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    Öğe
    Synthesis and Characterization of Novel Thiourea Derivatives and Their Nickel and Copper Complexes
    (Hindawi Ltd, 2013) Binzet, Gun; Kavak, Gulten; Kulcu, Nevzat; Ozbey, Suheyla; Floerke, Ulrich; Arslan, Hakan
    New benzoyl thiourea derivatives and their nickel and copper complexes were synthesized. The structure of the synthesized compounds were confirmed by elemental analysis, FT-IR, and H-1 NMR techniques. Four of the synthesized compounds are analyzed by X-ray single crystal diffraction technique. Whereas N,N-dimethyl-N'-(4-fluorobenzoyl) thiourea, N, N-diethyl-N'-(4-fluorobenzoyl)thiourea, and N,N-di-n-butyl-N'-(4-fluorobenzoyl)thiourea crystallize in the monoclinic system, bis(N,N-di-n-propyl-N'-(4-fluorobenzoyl)thioureato) nickel(II) complex crystallizes in the triclinic system. These ligandmolecules formdimers through strong intermolecular hydrogen bonds such as N-H center dot center dot center dot S, C-H center dot center dot center dot, and N-H center dot center dot center dot O. Moreover, there are different types of intramolecular interactions in the crystal structures. Bis(N,N-dimethyl-N'-(4-fluorobenzoyl)thioureato) nickel(II) complex has a nearly square-planar coordination. The distance of nickel atom from the best plane through the coordination sphere is 0.029 angstrom.
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    Öğe
    Synthesis and Structures of N,N-dialkyl-N?-(2-methylbenzoly, 4-flourobenzoyl) thiourea derivatives.
    (Int Union Crystallography, 2009) Kavak, Gulten; Binzet, Gun; Kulcu, Nevzat; Ozbey, Suheyla
    [Abstract Not Available]