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Subject: Glutathione transferase

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    Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Cellular Defense Enzyme Profile for Non-Cytotoxic and Phenol Enriched Extracts of heliotropium Europaeum, carlina Oligocephala and echinops Ritro
    (Asian Network Scientific information-ansinet, 2018) Isgor, Belgin S.; İşgör, Sultan Belgin; Isgor, Yasemin G.; Geven, Fatmagul; İşgör, Sultan Belgin; Chemical Engineering; Chemical Engineering
    Background and Objective:The discovery of traditional plants with some medicinal properties, verifying their biological targets and the bioassay guided standardization of their active components are the particular interest of diverse research groups recently. These efforts may help to revise the therapy modalities with natural product supplements. In this context, the possible biological targets of plants, namely Heliotropium europaeum, Carlina oligocephala and Echinops ritro, with no known medicinal value but recognized for their region specific traditional use, were evaluated. Here, the biological targets were enzymes of the antioxidant and xenobiotic defense mechanisms, with roles on inflammatory response. Materials and Methods: Cytotoxicity analyses were performed by using human promyelocytic (HL60) and chronic myelogenous leukemia (K562) cells for circulating models and breastadenocarcinoma (MCF7) cells for epithelial model to evaluate the non-toxic dose range of extracts by virtue of XTT and trypan blue. The target aimed effectiveness of these plants were determined with dose response profiles and IC50 values against glutathione peroxidase (GPX), glutathione transferase(GST),catalase (CAT) and superoxide dismutase (SOD) targets, as well as their capacity to reduce free radicals (DPPH) and non-radical hydrogen peroxide (H2O2). For standardization purposes, all extract concentrations were brought to 23.81 mg L-1 GAE and dilutions were made from these stocks. The IC50 values were determined by nonlinear regression analysis, with sigmoidal dose-response 4-parameter logistic equation. Results: The results showed that the best DPPH and H2O2 scavenging was observed with E ritro extracts. On the contrary, the best enzyme inhibition profile was observed with H europaeum against CAT, SOD, GPX and GST targets. Among the enzymes evaluated, all plants with different fractions also exerted strong GPX and CAT inhibition. Conclusion: The enzyme profiling of extracts may reveal the medicinal value of herbal remedies, by identifying their effects on cellular targets. In addition to define how reasonable the use of plants in traditional and complementary medicine (TCM) practices,these efforts may help to improve the standardized supplement preparations to benefit therapeutics with reduced efficiency due to inference with cellular defense and drug resistance enzymes, or both.
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    Review
    Citation - Scopus: 4
    Kinases and Glutathione Transferases: Selective and Sensitive Targeting
    (Higher Education Press Limited Company, 2011) Isgor,Y.G.; Isgor,B.S.
    Kinases, representing almost 500 proteins in the human genome, are responsible for catalyzing the phosphorylation reaction of amino acid residues at their targets. As the largest family of kinases, the protein tyrosine kinases (PTKs) have roles in controlling the essential cellular activities, and their deregulation is generally related to pathologic conditions. The recent efforts on identifying their signal transducer or mediator role in cellular signaling revealed the interaction of PTKs with numerous enzymes of different classes, such as Ser/Thr kinases (STKs), glutathione transferases (GSTs), and receptor tyrosine kinases (RTKs). In either regulation or enhancing the signaling, PTKs are determined in close interaction with these enzymes, under specific cellular conditions, such as oxidative stress and inflammation. In this concept, intensive research on thiol metabolizing enzymes recently showed their involvement in the physiologic functions in cellular signaling besides their well known traditional role in antioxidant defense. The shared signaling components between PTK and GST family enzymes will be discussed in depth in this research review to evaluate the results of recent studies important in drug targeting for therapeutic intervention, such as cell viability, migration, differentiation and proliferation. © Higher Education Press and Springer-Verlag Berlin Heidelberg 2011.