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Öğe Adsorption isotherms, kinetics, thermodynamics and desorption studies for uranium and thorium ions from aqueous solution by novel microporous composite P(HEMA-EP)(ELSEVIER SCIENCE BV, 2013) Akkaya, Recep; Akkaya, BirnurIn this research, a novel composite, poly(2-hydroxyethylmethacrylate-expanded perlite) [P(HEMA-EP)], was synthesized and its adsorptive features were investigated. P(HEMA-EP)'s adsorptive features were evaluated for UO22+ and Th4+ ions in terms of the dependency upon the ion concentration, pH, temperature, and time. P(HEMA-EP) was able to bind UO22+ and Th4+ ions with strong chemical affinity. The adsorption results were fitted to the classical Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models. P(HEMA-EP) was also used to study the removal of UO22+ and Th4+ ions from aqueous solutions in a batch system. The adsorption capacity (X-L) of UO22+ and Th4+ ions was found to be 0.29 and 0.44 mol kg(-1), respectively. The kinetic data corresponds well to the pseudo-second-order equation. Changes in the enthalpy and entropy values demonstrated that the overall adsorption process was spontaneous (Delta G < 0), endothermic (Delta H > 0), and had increased entropy (Delta S > 0), as expected. The reusability of the composites was confirmed for five sequential reuses. (C) 2012 Elsevier B.V. All rights reserved.Öğe Bentonite-acrylamide-histidine-Cu(II) Microcomposite for Cytochrome c Adsorption(ISMITHERS, 2012) Akkaya, Birnur; Akkaya, RecepBentonite-acrylamide-histidine with an average particle diameter of 200-1000 mu m was produced by bulk polymerization of bentonite, acrylamide, bisacrylamide, AIBN and histidine. Bentonite-acrylamide-histidine-Cu(II) microcomposite was prepared by loading copper ions. The microcomposite was characterized by scanning electron microscopy (SEM), specific surface area and elemental analysis. Cytochrome c adsorption studies were performed, for the first time, by using the new metal chelated affinity support (bentonite-acrylamide-histidine-Cu(II)) microcomposite in batchwise experiments.Öğe Characterization of thermostable beta-amylase isozymes from Lactobacillus fermentum(ELSEVIER SCIENCE BV, 2016) Kocabay, Samet; Cetinkaya, Serap; Akkaya, Birnur; Yenidunya, Ali FazilA strain of Lactobacillus fermentum producing two isozymes of a 20 kDa beta-amylase was isolated from the faecal sample of a newborn. The starin was identified by sequencing its 16S rRNA gene. The two beta-amylase isozymes were resolved and visualized by two dimensional protein gel electrophoresis (2-D gel electrophoresis). Some of the physical and biochemical properties of the enzymes were characterized. The beta-amylase displayed two optimum pH s, 5.0 and 10.0 and two optimum temperatures, 45 degrees C and 37 degrees C, respectively. The isozymes hydrolyzed different substrates: glycogen at pH 5.0, and corn starch at pH 10.0. The activity did not require Ca2+, though the activity at pH 10.0 was enhanced in the presence of 5.0 mM and 10.0 mM CaCl2, 110% and 130%, respectively. (C) 2016 Elsevier B.V. All rights reserved.Öğe Concanavalin a immobilized magnetic poly(glycidyl methacrylate) beads for antibody purification(WILEY-BLACKWELL, 2012) Akkaya, Birnur; Yavuz, Handan; Candan, Ferda; Denizli, AdilConcanavalin A (Con A) immobilized magnetic poly(glycidyl methacrylate) (mPGMA) beads in monosize and spherical for (1.62 mu m in diameter) were used for the purification of human immunoglobulin G (IgG) from human plasma. Con A was immobilized by covalent binding onto the mPGMA beads. The maximum IgG adsorption on the mPGMA-Con A beads was observed at pH 6.0. The nonspecific IgG adsorption onto the plain mPGMA beads was very low (0.22 mg/g). Scatchard analysis of the adsorption isotherm for IgG on mPGMA-Con A beads showed an affinity constant (Ka) of 1.39 x 105 M-1 and a theoretical maximum adsorption capacity of 109.1 mg/g. An apparent IgG adsorption capacity of 66.2 mg/g was observed under the experimental conditions. IgG adsorption capacity from human plasma was observed as 48.0 mg/g. The adsorption of human serum albumin from plasma was 2.0 mg/g. The total protein adsorption was determined to be 50.0 mg/g. IgG molecules could be repeatedly adsorbed and eluted with the mPGMA-Con A beads without noticeable loss in the IgG adsorption capacity. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Öğe Concanavalin a Immobilized Monosize and Magnetic Poly(glycidyl Methacrylate) Beads for Use in Yeast Invertase Adsorption(TAYLOR & FRANCIS INC, 2009) Akkaya, Birnur; Uzun, Lokman; Altintas, Evrim Banu; Candan, Ferda; Denizli, AdilConcanavalin A (Con A) immobilized monosize and magnetic poly(glycidyl methacrylate)[m-poly(GMA)] beads were investigated for specific adsorption of yeast invertase from aqueous solutions. m-Poly(GMA) beads (1.6 m in diameter) were prepared by dispersion polymerization in the presence of Fe3O4 nanopowder. The epoxy groups of m-poly(GMA) beads were opened by base catalyses. Then, Con A was immobilized by covalent binding onto the beads. Con A immobilization amount was 12.5 mg/g. The invertase adsorption capacity of the m-poly(GMA)/Con A beads was 111 mg/g. The maximum invertase adsorption on the m-poly(GMA)/Con A beads was observed at pH 5.5. The optimum activity for both free and adsorbed invertase was observed at 50C. Vmax values were determined as 330 U/mg and 292 U/mg enzyme, for free and adsorbed invertase, respectively. KM values were found to be the same for free and adsorbed invertase (20 mM). Adsorption of invertase via Con A improved the pH stability of invertase. Thermal stability also increased with adsorption. The adsorbed enzyme activity was found to be quite stable in repeated experiments.Öğe Cross-Linked Bentonite-Acrylamide-histidine-Based Metal-Chelate Affinity Microcomposites for Lysozyme Separation From Egg White(TAYLOR & FRANCIS INC, 2012) Akkaya, Birnur; Akkaya, RecepAmong different adsorbents, a new support for immobilized metal affinity chromatography was used for lysozyme separation from egg white. For this purpose, acrylamide, bisacrylamide, bentonite, and L-histidine in the presence of an initiator (azobisisobutyronitrile, AIBN) were mixed and bentonite-acrylamide-histidine microcomposites were prepared by bulk polymerization. Characterization studies were performed by SEM, FT-IR, XRD, and BET. Specific surface area of the bentonite and BABH microcomposite was found to be 33.4 and 1.42 m2/g, respectively. Cu2+ ions (20 mu mol/g) were chelated on these bentonite-acrylamide-histidine (50 mu mol/g L-histidine incorporation) microcomposites. The lysozyme adsorption capacity of the Cu2+ ions chelated microcomposites increased the lysozyme adsorption up to 100 mg/g while the lysozyme adsorption capacity of the bentonite-acrylamide-histidine was 24 mg/g. More than 89% of the adsorbed lysozyme was desorbed in 1 h in the desorption medium containing 1.0 M NaCl. Bentonite-acrylamide-histidine-Cu(II) was used for the purification of lysozyme from chicken egg white. The purity of lysozyme was estimated by SDS-PAGE. Specific activity of the purified lysozyme was found as 50,000 U/mg using Micrococcus lysodeikticus as substrate. The new metal-chelate affinity microcomposites were suitable for repeated use for five cycles without a noticeable loss of capacity.Öğe A Crosslinked Carboxylic Acid Containing Cation Exchange Monolithic Cryogel for Human Serum Albumin Separation(TAYLOR & FRANCIS INC, 2012) Akkaya, Birnur; Akkaya, RecepFor this work, we synthesized poly(N-isopropylacrylamide-acrylamide)-acrylic acid (poly(NIPAM-Am)-AAc) monolithic cryogel for a human serum albumin separation (HSA) from a protein mixture (human serum immunoglobulin, human serum albumin and lysozyme) and performed HSA adsorption studies using the cryogel to do continuous system experiments in a syringe column connected by a peristaltic pump. Poly(NIPAM-Am)-AAc with a pore size of 10-100 mu m was produced by free radical polymerization that proceeded in an aqueous solution of monomers frozen inside a syringe column. The monolithic poly(NIPAM-Am)-AAc cryogel was characterized by performing swelling studies, FTIR and SEM that showed a swelling ratio of 6.2 g H2O/g dry cryogel. The maximum HSA adsorption by the cryogel was 42.5 mg/g polymer at pH 4.0 in a 50 mM acetate buffer. We also studied the effect of two different temperatures (25 and 40 degrees C). The higher temperature increased the adsorption capacity of the cryogel. HSA molecules could be reversibly adsorbed and desorbed five times with the same poly(NIPAM-Am)-AAc cryogel without a noticeable loss of their HSA adsorption capacity. The synthesized cryogel was used to separate albumin from the protein mixture. Adsorbed albumin was eluted by changing the pH of the buffer (pH 7.0 and 25 degrees C). Poly(NIPAM-Am)-AAc monolithic cryogel behaved as a cation exchange column because of its functional carboxylic group.Öğe Drug delivery behavior of magnetic composite: In vitro study(Ibn Sina Trust, 2024) Akkaya, Birnur; Yerliyurt, Beyza NurBackground One method for delivering the medication to the intended location and achieving the desired therapeutic effect is controlled drug release. Compared to typical release systems, controlled medication release systems offer fewer potential adverse effects and can increase patient comfort by prolonging the time intervals between drug intakes. Expanded perlite modified composite were used as drug carrier materials in the current investigation because of its excellent adsorption capability. Aim: Using magnetic poly(hydroxyethylmethacrylate-expanded perlite) (m-p(hema-ep)) composite material, doxorubicin release was examined in this work. Methodolgy First, a magnetic p(hema-ep) composite was created for this purpose and examined using SEM, FTIR, and swelling tests. The medication doxorubicin served as a model. Tests for reusability were conducted. The synthesized magnetic p(hema-ep) composite was shown to be capable of being recycled ten times without losing effectiveness. On the C6 cell line, the material and the material that had been loaded with doxorubicin were subjected to cytotoxicity tests under magnetic field. Results The impacts of variables like pH, time, temperature, on drug release were examined as a consequence of the characterisation procedure. The ideal release parameters were found to be 80% release at pH 4.5, 70% release is seen at 7.4, and temperature 22 degrees C, under magnetic field. Conclusion: The anti-cancer medication doxorubicin (Dox) was used as a model drug because it is widely used in cancer treatment and is simple to quantify using methods like UV-visible spectroscopy. There are enhanced doxorubicin release under magnetic field.Öğe IgG purification by bentonite-acrylamide-histidine microcomposite(ELSEVIER SCIENCE BV, 2012) Akkaya, BirnurIn this work, a new microcomposite composed of bentonite, acrylamide and histidine, as a pseudospecific ligand, was synthesized by bulk polymerization. The aim of this study was to improve IgG adsorption capacity of bentonite by incorporating histidine. The surface areas of the bentonite and bentonite-acrylamide-histidine microcomposites were 33.4 and 1.42 m(2)/g, respectively. The amount of histidine was found to be 50 mu mol/g bentonite via elemental analysis. Adsorption capacity was at the value of 100 mg/g from aqueous solution while adsorption capacity was 108 mg/g from human plasma with a purity of 90%. IgG biomolecules were able to be adsorbed and desorbed five times by using the same microcomposites without significant loss in their adsorption capacity. (C) 2011 Elsevier B.V. All rights reserved.Öğe In Silico Studies of Synthetic Sulfatide as a Potential Drug Candidate Against Covid-19(2022) Kocabay, Samet; Alagöz, Mehmet; Bakır, Hıncal Gokhan; Akkaya, BirnurSulfatides play various roles in many biological processes such as cancer metastasis, viral infections and regulation in nerve cells. The sulfatide molecules are related with hypertension diseases in which ACE2 (Angiotensin converting enzyme) is important for regulating blood pressure. ACE2 is also a key receptor for Covid-19 and highly expressed many different tissue types. Understanding the interaction between the sulfatides and ACE2 might be a key factor to develop potential novel treatments against Covid-19. Here we studied the interaction of main protease enzyme (6LU7) of Covid-19 with native sulfatide(A), chitosan based synthetic sulfatide(B) and inhibitor N3, through in silico studies such as molecular docking, molecular dynamics, ADMET prediction and target selection analysis. The compounds A, B and N3 bind the virus protease enzyme with docking score of -5.420, -6.009, -6.161 kcal/mol respectively indicates synthetic sulfatide binds better than native sulfatide and comparable to N3. Besides, molecular dynamics studies were carried out to reveal the stability of the complexes of interest. ADMET and target prediction studies carried out to reveal pharmacological properties and toxicity of the complexes and synthetic sulfatide found to be a drug-like molecule. We anticipate that computational investigation of virus interaction mechanisms will be an important starting point for experimental research in drug development efforts against Covid-19.Öğe Inhibitory effects of carvacrol on glucansucrase from Streptococcus mutans and salivary α-amylase: in silico and in vitro studies(Tubitak Scientific & Technological Research Council Turkey, 2025) Kocabay, Samet; Alagoz, M. Abdullah; Akkaya, BirnurBackground/aim: Streptococcus mutans produces glucansucrase, an enzyme that converts sucrose into lactic acid, which lowers the pH in the oral environment and leads to tooth enamel demineralization, a key factor in dental caries. Additionally, glucansucrase facilitates the formation of extracellular polysaccharides, which promote bacterial adhesion to tooth surfaces. This study investigates the inhibitory effects of carvacrol, a natural compound, on glucansucrase activity both in vitro and in silico. Materials and methods: Glucansucrase enzyme was purified from S. mutans. The inhibitory effects of carvacrol against glucansucrase enzyme were investigated both in vitro and in silico. Results: In the presence of 50 mM carvacrol, glucansucrase and salivary amylase activities were reduced by 51.25% and 14.85%, respectively. Carvacrol did not significantly inhibit (4.73%) the salivary amylase enzyme at 10 mM. Glucansucrase activity decreased by 51.63% in the presence of 10 mM acarbose, which was used as a positive control in glucansucrase enzyme studies. Acarbose inhibited salivary amylase with 82.54% loss of enzyme activity in the presence of 1 mM acarbose. The docking score obtained for carvacrol was -5.262 kcal/mol, while that obtained for acarbose was -6.084 kcal/mol. We carried out molecular dynamics simulation studies for 100 ns to determine the stability of carvacrol in the active site of the protein. Carvacrol demonstrated stable binding to glucansucrase with hydrogen bonds and interactions at key residues (ASP477, GLN960, and ASP909), confirmed by molecular dynamics simulations. Carvacrol remained stable between 16 and 100 ns. Conclusion: Carvacrol selectively inhibits glucansucrase without significantly affecting salivary amylase, making it a more targeted inhibitor compared to acarbose, which inhibits both enzymes. Docking studies indicated that while carvacrol has a lower binding affinity than acarbose, its stable interaction with the enzyme suggests sustained inhibitory action. These findings highlight carvacrol as a promising natural compound for preventing dental caries, offering a more selective alternative to traditional inhibitors. Further in vivo studies are necessary to assess its therapeutic efficacy and safety in clinical applications for oral health.Öğe Investigation of inhibitory effect of sulfated chitosan oligomer on human heparanase enzyme: in silico and in vitro studies(Taylor & Francis Inc, 2024) Kocabay, Samet; Alagoez, M. Abdullah; Akkaya, BirnurDeaths from cancer are widespread worldwide and the numbers continue to increase day by day. During the disease progression of cancer in cells, many of its metabolic activities change. Increased heparanase enzyme release is just one example. Following heparanase enzyme activity, many molecules interact with the remodeling of glycosaminoglycan structures, which triggers the release of different enzymes, cytokines, and growth factors, including fibroblast growth factors (FGF1 and FGF2), vascular endothelial growth factor (VEGF), hepatocyte growth factor, transforming growth factor beta and platelet-derived growth factor. These are the most important factors in metastasis due to the formation of new vascular structures caused by those elements. To reduce tumor growth and metastasis, various drugs have been designed by modifying chitosan and its derivatives. In this study, we used chitosan oligomer (A), sulfated chitosan oligomer (ShCsO) (B), heparin (C), phosphate monomer (D1) of PI-88 and sulfate monomer (D2) of PI-88 as heparanase inhibitors. We modified the chitosan oligomer with chlorosulfonic acid to synthesize ShCsO to investigate its inhibitory effects on human serum heparanase. Also examined were molecular docking; molecular dynamics (MD); adsorption, distribution, metabolism, elimination and toxicity (ADMET); and target prediction. ShCsO decreased enzyme activity at a concentration of 0.0001 mg/mL. The docking scores of A, B and C from in silico studies were -6.254, -6.936 and -6.980 kcal/mol, respectively, and the scores for the two different PI-88 monomers were -5.741 and -5.824 kcal/mol. These results show that ShCsO may be a potential drug candidate for treating cancer. Communicated by Ramaswamy H. SarmaÖğe Lektin afinite kromatografisi ile antikor saflaştırılması(Cumhuriyet Üniversitesi, 2009) Akkaya, Birnur; Denizli, Adil; Candan, FerdaBu çalışmada, Konkanavalin A (Con A) immobilize eş boyutlu manyetik poli-glisidil metakrilat (GMA) mikropartiküller kullanılarak, kesikli ve MSFB (Manyetik olarak kararlılaştırılmış akışkan yatak) sistemde sulu çözeltiden ve insan serumundan IgG (İmmünoglobulin G) saflaştırılması çalışıldı. M-poli(GMA) eş boyutlu mikrokpartiküller, Fe3O4 nanopartikül varlığında dispersiyon polimerizasyon yöntemi ile sentezlendi. FT-IR, 1H NMR, SEM, ESR, VSM analizleri m-poli(GMA)'nın karakterizasyonu için kullanıldı.Manyetik eş boyutlu poli(GMA) mikropartiküllerdeki epoksi halkaları alkali koşullarda açılarak Con A hidroksil uzantılarından mikropartiküle kovalent olarak bağlandı. Maksimum Con A immobilizasyon değeri pH 7.4 (0,1 M fosfat tamponu)'de 4 oC'de 12.5 mg g-1 olarak bulundu. M-poly(GMA)-Con A mikrokürelere kesikli ve MSFB sistemde maksimum IgG adsorpsiyon kapasiteleri sırasıyla 35.5 ve 37.7 mg g-1, olarak saptandı. Her iki sistemde de maksimum IgG adsorpsiyon kapasitesi pH 6.0'da (0.1 M fosfat tamponu) saptandı. MSFB sistemde, akış hızı ve manyetik alan çalışmaları da yapıldı. Adsorpsiyon kapasitesi, akış hızı 1.0'den 4.0 mL dak-1' ya yükseldikçe 37.7'den 10.9 mg g-1 değerine düşmektedir. Manyetik alan artırıldığında ise, artan manyetik alan neticesinde adsorplanan IgG değeri 37.7'den 18.0 mg g-1 değerine düşmüştür. Her iki sistemde polimerik mikropartiküle adsorplanan IgG'nin desorpsiyonu için etilen glikol + glukoz kullanılarak gerçekleştirildi. Aynı partikül kullanılarak yapılan on tekrarlı adsorpsiyon- desorpsiyon döngüsü sonucunda partikülün adsorpsiyon veriminde anlamlı değişme olmadığı görüldü.M-poli(GMA)-Con A kullanılarak insan serumundan yapılan IgG adsorpsiyon çalışmaları sonucu gram partikül başına maksimum adsorpsiyon 48 mg g-1 olarak bulundu. 2.0 M NaCl insan serumundan saflaştırma çalışmalarında partiküle adsorplanan IgG'nin desorplanmasında desorplayıcı ajan olarak kullanıldı. Saflaştırılan IgG'nin saflık kontrolü ise SDS-PAGE yöntemi ile yapıldı. Kan çalışmaları ve desorpsiyon çalışmaları sonucunda ölçümlerin hepsi ELISA yöntemi kullanılarak yapıldı. Adsorpsiyon ve desorpsiyon çalışmaları süresince IgG molekülünün yapısında değişme olup olmadığı spektroflorimetrik çalışmalar ile araştırıldı.Çalışmaların son kısmını oluşturan SPR (Yüzey Plazmon Rezonans) çalışmaları ise Con A ve IgG arasındaki etkileşimin kinetik açıdan incelendiği aşamadır. Bu amaç doğrultusunda SPR çipe immobilize edilen Con A ile önce plazmon açısı saptandıktan sonra kinetik çalışmalar yapıldı. Kinetik ve bağlanma sabitlerinin bulunabilmesi için kinetik veriye üç farklı izoterm (Langmuir, Freundlich ve Langmuir-Freundlich) uygulandı. Sonuçlardan en uygun grafiğin Langmuir olduğu anlaşıldı.Anahtar Kelimeler: m-poli(GMA), ConA immobilizasyon, dispersiyon polimerizasyon, lektin afinite kromatografisi, IgG saflaştırma.Öğe Mercury leads to abnormal red blood cell adhesion to laminin mediated by membrane sulfatides(ELSEVIER SCIENCE BV, 2019) Akkaya, Birnur; Kucukal, Erdem; Little, Jane A.; Gurkan, Umut A.Exposure to mercury is associated with numerous health problems, affecting different parts of the human body, including the nervous and cardiovascular systems in adults and children; however, the underlying mechanisms are yet to be fully elucidated. We investigated the role of membrane sulfatide on mercuric ion (Hg2+) mediated red blood cell (RBC) adhesion to a sub-endothelial matrix protein, laminin, using a microfluidic system that mimics microphysiological flow conditions. We exposed whole blood to mercury (HgCl2), at a range of concentrations to mimic acute (high dose) and chronic (low dose) exposure, and examined RBC adhesion to immobilized laminin in microchannels at physiological flow conditions. Exposure of RBCs to both acute and chronic levels of Hg2+ resulted in elevated adhesive interactions between RBCs and laminin depending on the concentration of HgCl2 and exposure duration. BCAM-Lu chimer significantly inhibited the adhesion of RBCs that had been treated with 50 mu M of HgCl2 solution for 1 h at 37 degrees C, while it did not prevent the adhesion of 3 h and 24 h Hg2+-treated RBCs. Sulfatide significantly inhibited the adhesion of RBC that had been treated with 50 mu M of HgCl2 solution for 1 h at 37 degrees C and 0.5 mu M of HgCl2 solution for 24 h at room temperature (RT). We demonstrated that RBC BCAM-Lu and RBC sulfatides bind to immobilized laminin, following exposure of RBCs to mercuric ions. The results of this study are significant considering the potential associations between sulfatides, red blood cells, mercury exposure, and cardiovascular diseases.Öğe Modification by natural sources to reduce immuno-reactivity of milk proteins(2020) Akkaya, Recep; Akkaya, Birnur; Çetinkaya, SerapThe main aim of the current study was to reduce the IgE-binding capacity of cow’s milkthrough its chemical modification by natural source treatment. The presence of childrenallergic responses to cow's milk has become a growing concern in the world. A possibleapproach to reduce protein allergen is to block IgE-binding epitopes of protein allergen byvarious methods. One of them is protein glycation. We wanted to examine effect of someadditives especially lemon juices on milk protein modification by using electrophoresis and2D gel electrophoresis. As a result of this study lemon juice (ascorbic acid) enhanced glycationof milk proteins.Öğe N-methacryloyl-(L)-histidine methyl ester carrying porous magnetic beads for metal chelate adsorption of cytochrome c(ELSEVIER SCIENCE BV, 2007) Akkaya, Birnur; Uzun, Lokman; Candan, Ferda; Denizli, AdilA magnetic metal-chelate adsorbent utilizing N-methacryloyl-(L)-histidine methyl ester (MAH) as a metal-chelating ligand was prepared. MAH was synthesized using methacryloyl chloride and L-histidine methyl ester. Magnetic beads with an average diameter of 50-100 mu m were produced by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and MAH carried out in a dispersion medium. Specific surface area of the magnetic beads was found to be 80 m(2)/g. Elemental analysis of the magnetic beads for nitrogen was estimated as 70 mu mol MAH/g polymer. Magnetic beads were complexed with the Cu2+ ions directly via MAH for the adsorption of cytochrome c from aqueous solutions. The cytochrome c adsorption on the mag-poly(EGDMA-MAH) beads was 51 mg/g. Cu2+ complexing increased the cytochrome c adsorption significantly. The maximum cytochrome c adsorption capacity of the Cu2+-chelated beads (carrying 68 mu mol Cu2+ per gram of polymer) was found to be 222 mg/g at pH 8.0 in phosphate buffer. Cytochrome c adsorption decreased with increasing temperature. Cytochrome c molecules could be reversibly adsorbed and desorbed ten times with the magnetic adsorbents without noticeable loss in their cytochrome c adsorption capacity. The resulting magnetic chelator beads posses excellent long term storage stability. (c) 2006 Elsevier B.V. All rights reserved.Öğe New Composite, Poly(Hydroxyethylmethacrylate-Expanded Perlite), for Single step Separation of Egg White Lysozyme(2018) Akkaya, Birnur; Akkaya, RecepIn this study, we investigated adsorption behaviour of lysozyme on poly(hydroxyethylmethacrylateexpanded perlite) [P(Hema-Ep)]. For this purpose, we synthesized P(Hema-Ep) composite by bulk polymerization and it was characterized by SEM, FTIR and swelling ratio. The fresh chicken egg white lysozyme was used as a model protein, had an isoelectric point (pI) 10.7 and molecular weight (MW) 14 kDa. Adsorption capacity was found 51 mg g-1 at room temperature and in 0.1 M pH=8.0 phosphate buffer. Experiments on desorption and reusability were also performed. It appears that P(Hema-Ep) composites can be used ten times without lost of efficiency. Lysozyme purification, without causing any denaturation, can be performed from chicken egg white by using this new synthesized composite in a single step.Öğe New Composite, Poly(Hydroxyethylmethacrylate-Expanded Perlite), for Single step Separation of Egg White Lysozyme(Sivas Cumhuriyet University, 2018) Akkaya, Birnur; Akkaya, RecepIn this study, we investigated adsorption behaviour of lysozyme on poly(hydroxyethylmethacrylate-expanded perlite) . For this purpose, we synthesized P(Hema-Ep) composite by bulk polymerization and it was characterized by SEM, FTIR and swelling ratio. The fresh chicken egg white lysozyme was used as a model protein, had an isoelectric point (pI) 10.7 and molecular weight (MW) 14 kDa. Adsorption capacity was found 51 mg g-1 at room temperature and in 0.1 M pH=8.0 phosphate buffer. Experiments on desorption and reusability were also performed. It appears that P(Hema-Ep) composites can be used ten times without lost of efficiency. Lysozyme purification, without causing any denaturation, can be performed from chicken egg white by using this new synthesized composite in a single step.Öğe New low-cost composite adsorbent synthesis and characterization(TAYLOR & FRANCIS INC, 2013) Akkaya, Recep; Akkaya, BirnurIn this research, a novel composite, poly(acrylamide-expanded perlite) [P(AAm-EP)], was synthesized and characterized. The chemical synthesis was achieved by using free-radical polymerization and a number of structural characterization methods, including Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET)-porosity, and swelling tests. Free-radical polymerization of acrylamide (AAm) over expended perlite (EP) was successfully performed. The effect of reaction variables, such as dosage of the initiator, total concentration of the reactants, reactant ratio, mixing time, temperature, and reaction time, were investigated in detail. Expended perlite was cross-linked with acrylamide to enhance its chemical resistance. P(AAm-EP) composite has a specific surface area of 31.7m(2) g(-1).Öğe New solvated Mo(VI) complexes of isatin based asymmetric bisthiocarbohydrazones as potent bioactive agent: synthesis, DFT-molecular docking studies, biological activity evaluation and crystal structures(Springer, 2024) Kaya, Yeliz; Ercag, Ayse; Kaya, Savas; Berisha, Avni; Akkaya, Birnur; Zorlu, YunusNew solvated Mo(VI) complexes were isolated from the reaction of [MoO2(acac)2] with asymmetric isatin bisthiocarbohydrazone ligands. The ligands were obtained from the reaction of isatin monothiocarbohydrazone with 3,5-dibromo salicylaldehyde (L1), 3,5-dichloro salicylaldehyde (L2) and 3-chloro-5-bromo salicylaldehyde (L3), respectively. In the complexes, the ligands serve as ONS donors and coordinate to the [MoO2]2+ nucleus. The bonding sites are azomethine nitrogen atom, phenolic oxygen atom and thiol sulfur atom. The sixth coordination site is completed by an oxygen atom from an ethanol solvent. The ethanol-coordinated Mo(VI) complexes, C1-C3, [MoO2L(EtOH)] (L: L1-L3), were characterized using elemental analysis, IR and 1H NMR spectroscopies, and conductivity measurements. By crystallizing ethanol-solvated solid complexes from an EtOH/DMSO mixture, DMSO-solvated complexes (C4-C6) suitable for X-ray crystallography were obtained. Crystal structure analysis supports the proposed complex structures and geometries, but the ethanol in the sixth coordination site has been replaced by DMSO. When the anticarcinogenic effects of the ligands and complexes (C1-C3) on the C6 cell line were examined, it was found that the complexes showed higher activity than the ligands. The C3 complex appears to have the best anti-cancer activity compared to doxorubicin. Additionally, all compounds were determined to have high total antioxidant capacity. Data obtained from theoretical studies (DFT and docking) support experimental studies.
