Yazar "Gundogdu, Cemal" seçeneğine göre listele

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    Effects of some heavy metals on the activities of carbonic anhydrase enzymes from tumorous and non-tumorous human stomach
    (2015) Yerlikaya, Emrah; Demirdag, Ramazan; Kufrevioglu, Omer Irfan; Gundogdu, Cemal
    In this study, in vitro effects of certain heavy metals on the human carbonic anhydrase enzyme were examined. Inhibitory effects of metal ions (Pb2+, Cu2+, Fe2+, Cr2+, Al3+, Ni2+, Mn2+, Cd2+, Zn2+, and Mg2+) were observed in tumorous and non-tumorous tissue. IC50 values were calculated for metals. The Cu2+, Zn2+, Ni2+, Cd2+ and Mg2+ IC50 values of tumorous tissue were calculated as 0.034 mM, 0.426 mM, 0.597 mM, 0.878 mM and 2.52 mM, respectively. The Cu2+, Zn2+, Ni2+, Cd2+ and Mg2+ IC50 values of non-tumorous tissue were calculated as 0.067 mM, 0.991 mM, 1.065 mM, 1.724 mM and 6.13 mM, respectively. Carbonic anhydrase activity was measured as described by Wilbur and Anderson. Hydratase activity was used to determine IC50 values. In this study, tumorous and non-tumorous human stomach tissues were selected due to the fact that among the diseases, stomach cancer has one of the highest mortality rates. Stomach cancer, a type of cancer affecting the digestive system, is a fatal disease in living systems. The effects of metals on the CA enzyme were investigated due to the extremely important role that CA enzymes play in living beings.
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    Purification of CA Isoenzymes from Human Cancerous Colon Tissue and Inhibitory Effects of Some Analgesics on Enzyme Activity
    (2012) Demirdag, Ramazan; Yerlikaya, Emrah; Kufrevioglu, Omer Irfan; Gundogdu, Cemal
    Carbonic Anhydrase (CA) is an enzyme which is responsible for the hydration of carbon dioxide to carbonic acid and it also takes places in many biological processes in the living organisms. In this study, CA isoenzymes (CA II and CA IX) together were purified 78.4 fold with a yield of 54.86 and specific activity of 106.67 by using Sepharose 4B-L-tyrosine sulfanilamide affinity chromatography. In SDS-PAGE molecular weights of CA II and CA IX were calculated as 29 kDa and 56 kDa respectively. Besides inhibitory effects of some analgesics on purified total enzyme was investigated. IC50 values were found as 0.0077, 0.025, 0.011 and 0.04 mM for dexketoprofen, pethidine, phenyramidol and tramadol respectively.
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    Öğe
    Purification of glutathione S-transferase isoenzymes from tumour and nontumour human stomach and inhibitory effects of some heavy metals on enzymes activities
    (2013-04) Demirdag, Ramazan; Yerlikaya, Emrah; Kufrevioglu, Omer Irfan; Gundogdu, Cemal
    In this study, glutathione S-transferase (GST) enzyme was purified from nontumour and tumour human gastric tissue and in vitro effects of heavy metals on the enzyme were examined. GST was purified 3089 fold with a specific activity of 20 U/mg and a yield of 78% from gastric tumour tissue; and 1185 fold with a specific activity of 5.69 U/mg and a yield of 50% from nontumour tissue by using glutathione-agarose affinity column, respectively. Enzyme purity was verified by SDS-PAGE and subunit molecular mass was calculated around 26 kDa. The molecular weight of the enzyme was calculated as 52 kDa by using Sephadex G-75 gel filtration column. Then, inhibitory effects of metal ions on the enzymes were investigated. Mg2+ and Cd2+ had inhibitory effect on the enzymes activities. Other kinetic properties of the enzymes were also determined.