EPR Spectroscopy of Dog-Rose Polyphenoloxidase

Authors: Çiğdem NUHOĞLU, Fatih UCUN, Enise AYYILDIZ, Y. Kemal YOĞURTÇU, Halis ŞAKİROĞLU, İrfan KÜFREVİOĞLU

Abstract: Polyphenoloxidase(PPO) of dog-rose fruit was extracted and purified through (NH\4)\2SO\4 precipitation and dialysis. The optimum conditions for this purpose, i.e., pH and temperature, were determined with 4-methylcatechol optimum pH and temperature and found to be pH 8.5 and 20\ci, respectively. The inhibition effect of ascorbic acid was investigated and the I_{50} value was found to be 1.57\times10^{-4} M. The activity of dog-rose PPO was investigated by electron paramagnetic resonance (EPR) at different pH levels and temperatures. The optimum conditions obtained from both spectrophotometry and EPR were compared.

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