| Purification of Glucose-6-Phosphate Dehydrogenase From Hazelnut (Corylus maxima Miller) and Investigation of Some Properties
In our study, glucose-6-phosphate dehydrogenase (G6PD, E.C. 1.1.1.49) was purified for the first time from hazelnut (Corylus maxima Miller) being abundant in Giresun (Turkey) and surroundings and some properties of the enzyme were investigated.
G6PD was purified 36.2-fold from hazelnut by homogenization, ammonium sulfate precipitation, hydroxylapatite column chromatography. Temperature of +4ºC was maintained during the purification process. The protein content was determined by Bradford’s and Warburg’s methods and the enzyme activity was measured spectrophotometrically at 37ºC according to Beutler’s and Betke’s methods at 340 nm.
The PAGE of the purified enzyme showed one activity band corresponding to 271 kDa molecular weight. SDS-PAGE showed that the enzyme was an octamer composed of 33.820 kDa subunits.
It was found that the purified glucose-6-phosphate dehydrogenase utilised only NADP+ as a coenzyme. The optimum temperature was found to be between 37-40ºC, and the optimum pH at pH=8.0. The activation energy of the reaction catalyzed by the enzyme was calculated as 5.01 kcal.mol-1.
The affinity of the enzyme against the D-glucose-6-phosphate and NADP+ was investigated Km values were for D-glucose-6-phosphate and NADP+ 1.9449 mM and 0.4192 mM, respectively. Vmax values were for D-glucose-6-phosphate and NADP+ 0.0514 U/mL and 0.0428 U/mL, respectively.
The effects of several inorganic, organic compounds, and some detergents on the enzyme activity was determined. Storage stability of the enzyme was also investigated.
TAŞSETEN Gökçe
Danışman :Prof.Dr.Süleyman TANYOLAÇ
Anabilim Dalı :Kimya
Programı :Organik
Mezuniyet Yılı :2008
Tez Savunma Jürisi :Prof.Dr.Süleyman Tanyolaç (Danışman)
Prof.Dr.Cemil İBİŞ
Prof.Dr.Ayşe Yusufoğlu
Prof.Dr.Serpil Göksel
Prof.Dr.Nüket ÖCAL (Y.T.Ü. Fen-Ed. Fak.)
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