Bioengineering / Biyomühendislik

Permanent URI for this collectionhttps://hdl.handle.net/11147/4529

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Publisher: search.filters.publisher.Türk Biyokimya Derneği

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  • Article
    Citation - WoS: 4
    A Src/Abl Kinase Inhibitor, Bosutinib, Downregulates and Inhibits Parp Enzyme and Sensitizes Cells To the DNA Damaging Agents
    (Türk Biyokimya Derneği, 2018) Kırmızıbayrak, Petek Ballar; Yılmaz, Sinem; Yılmaz, Sinem; Günal, Selin; Tepedelen, Burcu Erbaykent; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Background: Poly(ADP-ribosyl)ation (PARylation) catalyzed mainly by PARP1 is a highly regulated posttranslational modification associated with several pathways in cellular physiology and genotoxic deoxyribonucleic acid (DNA) damage response. PAR polymers and PARP enzyme function in DNA integrity maintenance and several PARP inhibitors have entered clinical phase studies for cancer therapies. Material and methods: The effect of bosutinib, a dual Src/Abl kinase inhibitor, on PARylation was fluorometrically measured. The cytotoxic and chemosensitizing effects were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of DNA repair proteins and PARP enzyme were examined by immunoblotting. Results: In this study, bosutinib is characterized as a novel PARP inhibitor. Bosutinib inhibited oxidative stress-induced cellular PARylation and nuclear foci formation by downregulating PARP1 levels. Bosutinib was found to be more cytotoxic on Capan1 cells with BRCA2 mutation. Furthermore by acting as a chemosensitizer, bosutinib enhanced the cytotoxicity of doxorubicin (DOXO) and etoposide (ETP) by decreasing phosphorylation of DNA repair enzymes checkpoint kinase 1 (Chk1) and ataxia-telangiectasia mutated (ATM). Conclusion: By inhibition of both PARP and DNA damage checkpoint kinases, bosutinib increased the phospho-H2AX levels, an early indicator of DNA double strand breaks.
  • Article
    Kinetic and Structural Characterization of Interaction Between Trypsin and Equisetum Arvense Extract
    (Türk Biyokimya Derneği, 2014) Uslu, Mehmet Emin; Bayraktar, Oğuz; Ceylan, Çağatay; Bayraktar, Oğuz; 03.08. Department of Food Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Objective: In this study the inhibitory effect of E. arvense extract on trypsin activity and the effect of trypsin on E. arvense extract were studied. In addition the nature of the interaction between the extract and trypsin was investigated. Methods: The inhibitory effect ethanol extract of E. arvense on trypsin activity was determined using trypsin enzyme assay. The structural effects of the extract-trypsin interaction for the extract were analyzed by FTIR. Finally, the HPLC analyses were carried out to analyze the individual components of the extract and the supernatant and soluble precipitate phases. Results: E. arvense extract was found to decrease total percent activity of trypsin to 5% in 24 hour at 24 °C. FTIR analyses indicated that the interaction between trypsin and E. arvense extract caused changes in the structure and hydrogen bonding behavior and composition of the extract proteins. These interactions also caused the extract lipids to accumulate in the insoluble precipitate phase. Most of the phenolics remained in the supernatant phase enhancing the inactivation of trypsin. However, the precipitated compounds were shown to be of apolar in nature as shown in the HPLC chromatograms. Conclusion: The methods that were used showed that the high phenolic content of E. arvense was the main reason for the inhibition of trypsin enzyme activity by denaturing the enzyme.