Yazar "Karaman, Muhammet" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    The Carboxylated Multi-walled Carbon Nanotubes/l-Asparaginase Doped Calcium-Alginate Beads: Structural and Biocatalytic Characterization
    (Springer, 2020) Ulu, Ahmet; Karaman, Muhammet; Yapici, Fatma; Naz, Mehmet; Sayin, Selin; Saygili, Eyup Ilker; Ates, Burhan
    The calcium-alginate/multi-walled carbon nanotube hybrid beads (Ca-ALG/MWCNT-COOH) as a novel kind of matrix were fabricated and characterized in detailed. l-Asparaginase (l-ASNase), which is important chemotherapeutic enzyme-drug in leukemia, was immobilized on the Ca-ALG/MWCNT-COOH hybrid beads. To the best of our knowledge, this is the first study using Ca-ALG/MWCNT-COOH hybrid beads for l-ASNase immobilization. Our characterization investigations displayed that the hybridization between ALG and MWCNT-COOH caused significant changes on the surface morphology and structure. ALG of 0.5% (w/v), CaCl2 of 0.2 M concentration, enzyme of 187.5 U and bead size of 2 mm was found to be best with respect to enzyme loading efficiency. The enzyme was loaded a high yield (97.0%) on these hybrid beads. Remarkably, the tolerance of immobilized enzyme developed towards temperature and pH changes. The maximum activity for the free enzyme was observed at 35 degrees C, pH 7.5, whereas the immobilized enzyme showed maximum activity at 45 degrees C pH 8.5. After immobilization, storage stability of enzyme improved and retained more than 70% of its initial activity after 4 weeks at ~ 30 degrees C as compared with free enzyme which showed only 20% of residual activity. After immobilization, Km value decreased 1.27-fold compared to free counterpart, indicating increased the affinity between the substrate and enzyme. Moreover, immobilized enzyme maintained more than 36% of its original activity even after consecutive 14 reuse. As result, it is worthy of noting that this kind of hybrid materials may become a promising support material for the immobilization of commercial enzymes in areas such as industrial and medical. Graphic
  • Küçük Resim Yok
    Öğe
    Imidazolinium chloride salts bearing wingtip groups: Synthesis, molecular docking and metabolic enzymes inhibition
    (Elsevier Science Bv, 2019) Yigit, Beyhan; Kaya, Ruya; Taslimi, Parham; Isik, Yilmaz; Karaman, Muhammet; Yigit, Murat; Ozdemir, Ismail
    A series of symmetrical imidazolinium chloride salts bearing secondary N-alkyl substituents were synthesized in good yield by the reaction of N,N'-dialkylethane-1,2-diamines and HC(OEt)(3) in the presence of NH4Cl. These salts were characterized by spectroscopic methods. All compounds were tested as enzyme inhibitory agents. These novel symmetrical imidazolinium chloride salts derivatives (3a-h) effectively inhibited the cytosolic hCA I and hCA II, BChE, alpha-glycosidase and AChE with K-i values in the range of 18.41-121.73 nM for hCA I, 12.50-63.12 nM for hCA II, 3.72-34.58 nM for AChE, 5.50-32.36 nM for BChE, and 94.72-364.51 nM for alpha-glycosidase, respectively. CA isoenzymes play a crucial roles including acid-base balance homeostasis by excreting and secreting protons (H+) due to the CO2 hydration, HCO3- reabsorption mechanisms, and renal NH4+ output. Also, the molecular modeling is an implementation for estimation of the binding proximity of symmetrical imidazolinium chloride salts bearing secondary wingtip groups and their inhibition mechanisms and kinetics in atomic levels at the catalytic domains. (C) 2018 Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Novel 2-methylimidazolium salts: Synthesis, characterization, molecular docking, and carbonic anhydrase and acetylcholinesterase inhibitory properties
    (Academic Press Inc Elsevier Science, 2020) Bal, Selma; Kaya, Ruya; Gok, Yetkin; Taslimi, Parham; Aktas, Aydin; Karaman, Muhammet; Gulcin, Ilhami
    In this work, structures of different imidazolium compounds were designed and synthesized. These compounds were synthesized from 2-methylimidazole and alkyl/aryl halides. Their structures were characterized by using H-1 NMR, C-13 NMR, FTIR spectroscopic techniques. All the synthesized compounds were tested for their inhibition activities on different enzymes. Inhibition experiments gave good and moderate results, proving their activities of these compounds as anticholinergics potential. These obtained novel 2-methylimidazolium salts (1a-e and 2a-e) molecules were effective inhibitors of the carbonic anhydrase I and II isozymes (hCA I and II) and acetylcholinesterase (AChE) enzymes with Ki values in the range of 26.45 +/- 6.49-77.60 +/- 9.53 nM for hCA I, 27.87 +/- 5.00-86.61 +/- 5.71 nM for hCA II, and 1.15 +/- 0.19-8.89 +/- 0.49 nM for AChE, respectively. AChE enzyme inhibitors are the most common drugs applied in the therapy of diseases such as senile dementia, Alzheimer's disease, ataxia, Parkinson's disease, and among others.
  • Küçük Resim Yok
    Öğe
    Novel amine-functionalized benzimidazolium salts: Synthesis, characterization, bioactivity, and molecular docking studies
    (Elsevier, 2020) Yigit, Murat; Yigit, Beyhan; Taslimi, Parham; Ozdemir, Ismail; Karaman, Muhammet; Gulcin, Ilhami
    A series of amine-tethered benzimidazolium salts were synthesized by the reactions between 1-(1-methyl-2-dimethylaminoethyl)benzimidazole and various alkyl halides. The characterization of the newly synthesized salts was done by spectroscopic methods. Also, 2e, 2f, and 2h have been docked into the catalytic active site hCA I, hCA II, AChE, BChE, and alpha-glycosidase enzymes. We have identified high binding affinity and explained inhibition mechanism of the compounds against the enzymes. These novel amine-functionalized benzimidazolium salts derivatives were good inhibitor compounds of the aglycosidase, hCA I and II isoforms, and both cholinesterase enzymes with K-i values in the range of 0.63 +/- 0.05-3.63 +/- 0.83 nM for a-glycosidase, 8.42 +/- 1.03-27.04 +/- 3.74 nM for hCA I, 7.94 +/- 0.74 - 21.82 +/- 5.81 nM for hCA II, 136.38 +/- 19.55-247.34 +/- 34.06 nM for BChE, and 124.24 +/- 13.94 - 283.55 +/- 54.06 nM for AChE, respectively. Among the inhibitors, 2e, 2e, 2f, 2f, and 2h were obtained to be the excellent inhibitors with Ki values of 8.42 +/- 1.03, 7.94 +/- 0.74,124.24 +/- 13.94,136.38 +/- 19.55, and 0.63 +/- 0.05 nM for hCA I, hCA II, AChE, BChE, alpha-glycosidase enzymes, respectively. The ability to model some metabolic enzymes receptors and theirs inhibitors in silico are important because they can save valuable resources and help to rationalize the mode of binding, and to design better inhibitors. (C) 2020 Elsevier B.V. All rights reserved.