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- MakaleYalnız künye2026Covalent Immobilization of Glutathione-S-Transferase onto Magnetic Iron Nanoparticles via Epichlorohydrin Spacer Arm
Kemal Caglar, M.; Gulesci, Nuri; Bilgin, Ramazan; Yucebilgic, Guzide
This study examined the synthesis of Fe₃O₄ magnetic nanoparticles (MNPs) and the covalent immobilization of glutathione-S-transferase (GSTs) onto these nanoparticles using an epichlorohydrin (ECH) spacer arm, as well as the optimal reaction conditions for both free and immobilized enzymes and the reusability of the immobilized enzyme. The optimal pH values for free and immobilized enzymes were established as 7.0 and 6.0, respectively. It was found that the ideal temperature for both free and immobilized enzymes was 37 and 40°C, respectively. Under the optimum conditions, the values of V_max for glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB) substrates of free GSTs enzyme were measured as 204.8 U/mg prot. and 194.3 U/mg prot., respectively. The immobilized GSTs enzyme's CDNB and GSH substrates had V_max values of 33.29 U/mg prot. and 33.08 U/mg prot., respectively. The free GSTs enzyme's CDNB and GSH substrates have K_m values of 0.201 mM and 0.1873 mM, respectively. GSH and CDNB have K_m values of 0.3042 mM and 0.2523 mM, respectively. At various temperatures, we contrasted the thermal stability of free and immobilized GSTs. The immobilized GSTs enzyme retained 50% of its activity after 20 reuses. After 30 days of storage at 25°C and 4°C, it was discovered that 18% and 32% of the free GSTs enzyme activity were preserved, and 30 days of storage at 25°C and 4°C resulted in 20% and 41% preserved enzyme activity for the immobilized enzyme, respectively.
- MakaleAçık Erişim2026Synthesis, Characterization, Biological Properties, and Sensor Applications of Novel Thiosemicarbazone Derivatives
Gezegen, Hayreddin; Özbek, Oguz; Topal, Meryem; Şahin, Hatice; Koçyiğit, Ümit M.
In this study, novel thiosemicarbazone derivative molecules (5a–j) were synthesized. The characterization of the synthesized molecules was carried out using 1H–, 13C–NMR, FT–IR, and Q–TOF spectroscopic techniques. Then, the inhibitory effect of these compounds was examined for human carbonic anhydrase I and II (hCA I, and II) and acetylcholinesterase (AChE). The hCA I II, and AChE were efficiently inhibited by synthesized thiosemicarbazone derivatives, with Ki values in the range of 0.293–1.666 µM for hCA I, 0.298–1.332 µM for hCA II, and 52.51–138.63 µM for AChE, respectively. Finally, the sensor properties of the synthesized thiosemicarbazone derivatives were investigated. The newly synthesized thiosemicarbazone derivative molecules exhibited high selectivity towards Pb2+ ions. The sensor prepared with 5a from these molecules had a Nernstian behavior of 28.8 ± 1.5 mV/decade and a low detection limit of 2.86 × 10−6 M in a wide concentration range of 1.0 × 10−1–1.0 × 10−5 M. The newly proposed sensor also had a wide pH working range (5.0–10.0), a very fast response time (5 s), and good reproducibility. The newly fabricated sensors were used as indicator electrodes for the potentiometric titration of Pb2+ ions with ethylenediaminetetraacetic acid (EDTA) and were successfully applied for the determination of Pb2+ ion content in different water samples.
- MakaleYayıncıda açık erişim2014Synthesis, X-ray structural characterization, NLO, MEP, NBO and HOMO-LUMO analysis using DFT study of Zn(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) dihydrate
Kaya, Afşin Ahmet; Demircioǧlu, Zeynep; Kaya, Elif Çelenk; Büyükgüngör, Orhan
A single crystal of Zn(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) dihydrate, formulated as C30H38N4O 14Zn, (I) has been obtained. According to experimental data, the complex can be characterized in the solid state as mononuclear, with a distorted octahedral stereochemistry. The distorted octahedral stereochemistry adopted by the complex was further confirmed by X-ray structure analysis of the current study, which consists of a six-coordinate Zn atom in a distorted octahedral environment constructed from two N atoms and four O atoms. The title compound crystallizes in the monoclinic space group C 2/c with a = 27.9248(18) Å, b = 8.5941(4) Å, c = 14.8344(11) Å, α = 90°, β = 108.651(5), γ = 90°, Z = 4. The molecular structure and geometry were also optimized using the B3LYP density functional theory method employing the 6-31G (d) basis set. Molecular electrostatic potential, frontier molecular orbital analysis, nonlinear optical properties and natural bond analysis for the title molecule are also described from the computational process.
- MakaleAçık Erişim2012Synthesis and characterization of new metallophthalocyanines bearing macrocyclic N 3O 2 groups on peripheral positions
Kaya, Elif Çelenk
The synthesis and characterization of new zinc(II) 3 , nickel(II) 4 and cobalt(II) 5 phthalocyanines complexes carrying macrocyclic N 3 O 2 groups on peripheral positions are described. The compounds were characterized by elemental analysis, IR, 1 H and 13 C NMR, UV-Vis and MS spectral data.