JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION, cilt.15, ss.1-6, 2019 (SCI-Expanded)
Polyphenol oxidase (PPO) was purified from tea leaves (Camellia sinensis) via affinity chromatography for the first time
and the purified enzyme was characterized. The purity of enzyme and molecular weight was determined by SDS-PAGE
and non-denaturing PAGE (native PAGE). Single bands were observed with both electrophoretically methods. The PAGE
results indicated that the molecular weight of PPO from tea leaf was approximately 50 kDa. The pH, temperature, and
kinetic parameters were studied. Km
values were 3.782 and 3.881 mM for catechol and 4-methylcatechol respectively. Vmax
values for catechol and 4-methylcatechol were also determined as 1.676 and 1.912 μmol/L min respectively. Additionally,
the inhibition effects of sodium metabisulfite, sodium sulfite, ascorbic acid, glutathione, dithioerythritol were investigated
on the enzyme activity and IC50,
Ki
values were calculated for these substances.