Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Institution Author: search.filters.institutionAuthor.Şanlı Mohamed, GülşahPublisher: search.filters.publisher.Elsevier

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Regio- and Stereo-Chemical Ring-Opening Reactions of the 2,3-Epoxy Alcohol Derivative With Nucleophiles: Explanation of the Structures and C-2 Selectivity Supported by Theoretical Computations
    (Elsevier, 2022) Gündoğdu, Özlem; Şanlı Mohamed, Gülşah; Çelebioğlu, Neslihan; Anıl, Barış; Şahin, Ertan; Şanlı Mohamed, Gülşah; Bozkaya, Uğur; Kara, Yunus; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    The ring-opening reactions of (1aS,2S,6bR)-5-ethyl-2-hydroxyhexahydro-4H-oxireno[2,3-e]isoindole-4,6(5H)-dione were investigated under very mild and nonchelated conditions. C-2 selective ring-opening products were obtained with nucleophilic additions such as Cl−, Br− and N3−. The exact configuration of (3aS,4R,5R,6S,7aS)-5-chloro-2-ethyl-4,6-dihydroxyhexahydro-1H-isoindole-1,3(2H)-dione was determined by X-Ray diffraction analysis which was obtained from the reaction of epoxy alcohol with HCl. On the other hand, theoretical computations were carried out to explain the regioselectivity in the ring opening reaction of epoxy alcohols. The results showed that the ring-opening reaction of both epoxy alcohols proceeds in a kinetically controlled manner and regioselectivity occurs depending on the transition state.
  • Article
    Citation - WoS: 39
    Citation - Scopus: 44
    Identification and Characterization of Novel Thermostable Alpha-Amylase From Geobacillus Sp. Gs33
    (Elsevier, 2020) Burhanoğlu, Tülin; Şanlı Mohamed, Gülşah; Sürmeli, Yusuf; Şanlı Mohamed, Gülşah; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    In this study, the heterologous expression and biochemical characterization of a thermostable alpha-amylase from Geobacillus sp. GS33 was investigated. The recombinant alpha-amylase was overexpressed in Escherichia coli BL21 (lambda DE) and purified via anion exchange and size-exclusion chromatography. The purified alpha-amylase had a molecular weight of about 60 kDa, and was active in a broad range of pH 3-10 and temperature (40-90 degrees C) withmaximumactivity at pH 7-8 and 60 degrees C. The enzyme retained 50% residual activity at 65 degrees C, but only 20% at 85 degrees C after 16 h. At pH 9 and pH 7, the residual activity at 65 degrees C was 50% and 30%, respectively. The enzymewas remarkably activated by Co2+, Ca2+, Mg2+, PMSF, DTT, and Triton X-100, but partially inhibited by Cu2+, methanol, hexane, ethanol, acetone, SDS, and Tween 20. A molecular phylogeny analysis showed that the enzyme's amino acid sequence had the closest connection with an alpha-amylase from Geobacillus thermoleovorans subsp. stromboliensis nov. 3D-structure-based amino acid sequence alignments revealed that the three catalytic residues (D217, E246, D314) and the four Ca2+ ion coordination residues (N143, E177, D186, H221) were conserved in alpha-amylase from Geobacillus sp. GS33. The temperature stability and neutral pH optimum suggest that the enzyme may be useful for industrial applications. (C) 2020 Elsevier B.V. All rights reserved.