Akademik Veri Yönetim Sistemi
Biology Bulletin, cilt.51, sa.1, ss.57-65, 2024 (SCI-Expanded, Scopus)
Abstract: A comparative study of the properties of healthy and apple scar skin viroid (ASSVd) infected apple fruit polyphenol oxidase (PPO) from apple cultivar Starking Delicious was carried out for the first time. PPOs from apple fruits were purified with a Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity chromatography. The activity of PPO in healthy and ASSVd infected apples was evaluated using the spectrophotometric method. PPO activity was determined using catechol as a substrate. Higher PPO activity was observed in ASSVd infected fruits as compared to healthy ones. Both healthy and ASSVd infected apples PPO produced two bands of approximately 66 and 40 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The pure enzymes were used to characterize enzyme at different pHs (from 4.5 to 9) and temperatures (from 15 to 45°C). For PPO from ASSVd-infected and healthy apples, the optimum pHs were 7.5 and 8.0, and the optimum temperatures were 15°C and 20°C, respectively. The Michaelis–Menten constant (Km) and the maximum reaction rate (Vmax) for healthy apple PPO were 10 mM and 3333.33 U/(mL min), whereas those for ASSVd infected apple PPO were 30 mM and 5000.00 U/(mL min), respectively.