Browsing by Author "Aldemir, S"

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Effects of Some Antibiotics on Glucose 6-Phosphate Dehydrogenase in Sheep Liver
(Czech Academy Agricultural Sciences, 2002) Çiftçi, M; Turkoglu, V; Aldemir, S
In vitro effects of penicillin, sulbactum, cefazolin, and amikacine on the activity of the enzyme glucose-6-phosphate dehydrogenase in sheep liver were investigated. Glucose 6-phosphate dehydrogenase was purified from sheep liver, using a simple and rapid method. The purification consisted of two steps, preparation and homogenate and 2'.5'-ADP Seprarose 4B affinity chromotography. As a result of the two consecutive procedures, the enzyme, having the specific activity of 11.76 EU/mg proteins, was purified with a yield of 35.72% and 11.913 fold. In order to control the enzyme purification SDS polyacrylamide gel electrophoresis (SDS-PAGE) was done. SDS-PAGE showed a single band for the enzyme. In addition , I-50 values of the antibodies were determined by plotting activity % vs. antibiotic concentration. I-50 values were 17.71 mM for penicillin, 27.38 mM for sulbactum, 28.88 mM for cefazolin, and 30.59 mM for amikacine.
Purification and Characterization of Glucose 6-Phosphate Dehydrogenase From Sheep Liver
(Tubitak Scientific & Technological Research Council Turkey, 2003) Türkoglu, V; Aldemir, S; Çiftçi, M
Glucose 6-phosphate dehydrogenase (D-glucose 6-phosphate: NADP(+) oxidoreductase, EC 1.1.1.49; G6PD) was purified from sheep liver by a simple and rapid method. The purification process consisted of two steps: preparation of the homogenate, and 2, 5'-adenosine diphosphate (ADP) Sepharose 4B affinity chromatography. Through the use of these two consecutive steps, the enzyme was purified with a yield of 35.6% and 1,920 fold, having the specific activity of 11.2 enzyme units (EU/mg protein). A K-M of 0.176 mM and a V-max of 0.0179 EU/ml were obtained for G6-P, and 0.0194 mM and 0.0223 EU/ml for NADP(+). Enzymatic activity was measured spectrophotometrically according to Beutler's method at 340 nm and optimal pH and assay temperature were determined. By means of a Lineweaver-Burk plot, the inhibitor constant for NADPH was determined to be K-i, 4.707 +/- 0.49 muM and it was shown to inhibit the enzyme in a non-competitive manner. The purification of enzyme was monitored by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE showed a single band at similar to55 kDa for the enzyme and gel filtration chromatography indicated it to be a dimer.