Aysun ŞENER, M. Ümit ÜNAL, Selin N YABACI

Extraction,Partial Purification And Characterisation Of Polyphenol Oxidase From Tea Leaf ( camellia sinensis )

Polifenol oksidaz (PFO) çay yapraklar›ndan ekstrakte edilip (NH4)2SO4 çökeltmesi, diyaliz ve iyon değişim kromatografisi ile kısmen saflaştırılmıştır. Test edilen substratlardan, 127.8 mM Km de¤eri ile 4-metilkateflol PFO için en iyi substrat olarak belirlenmiştir. PFO aktivitesi için optimum pH 6.02 olarak saptanmıştır. Enzim, 4.03-7.00 gibi genifl bir pH aral›¤›nda aktivite göstermifltir. PFO aktivitesi için optimum sıcaklık 30°C olarak bulunmufltur. 20-80 °C’ler aras›nda enzim maksimum aktivitesinin %70’den fazlasını korumuştur. Aktivasyon enerjisi (Ea) ve Z değerleri, sırasıyla, 58.301 kJ/mol (r2= 0.961) ve 39.68 °C (rr2= 0.965) olarak bulunmuştur. Test edilen inhibitörlerden L-sisteinin en düşlük inhibisyon derecesine sahip olduğu belirlenmiştir

Polifenol Oksidazın Çay ( camellia sinensis ) Yaprağından Ekstraksiyonu,Kısmi Saflaştırılması Ve Karakterizasyonu

Polyphenol oxidase (PPO) from tea leaves was extracted and partially purified through (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. Of the substrates tested, 4-methylcatechol was the best substrate for PPO with a Km value of 127.8 mM. The optimum pH for PPO activity was found to be 6.02. The enzyme showed high activity over a broad pH range of 4.03-7.00. The optimum temperature for PPO activity was 30 °C. The enzyme had more than 70% of the maximum activity between 20-80 °C. Energy of activation (Ea) and Z values were found to be 58.301 kJ/mol (r2= 0.961) and 39.68°C (r2= 0.965), respectively. Of the inhibitors tested, L-cysteine was the least potent inhibitor.

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