Polyphenol Oxidase from Apple (Malus domestica Borkh. cv Bramley's Seedling): Purification Strategies and Characterization
Article first published online: 31 MAY 2006
Journal of Food Science
Volume 71, Issue 1, pages C51–C58, January 2006
How to Cite
Ni Eidhin, D. M., Murphy, E. and O'Beirne, D. (2006), Polyphenol Oxidase from Apple (Malus domestica Borkh. cv Bramley's Seedling): Purification Strategies and Characterization. Journal of Food Science, 71: C51–C58. doi: 10.1111/j.1365-2621.2006.tb12388.x
- Issue published online: 31 MAY 2006
- Article first published online: 31 MAY 2006
- MS 20050398 Submitted 7/8/05, Revised 8/19/05, Accepted 10/21/05.
- polyphenol oxidase;
- diphenolase activity
ABSTRACT Polyphenol oxidase (PPO) was isolated from Bramley's Seedling apples with 75.7-fold purification and 26.5% recovery by ammonium sulfate precipitation, phenyl sepharose chromatography, ion exchange chromatography, and hydroxyapatite chromatography. Molecular weight was estimated to be about 45 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS PAGE). Optimum PPO activity was at pH 6.5 and greater than 50% activity was retained during storage for 72 h at pH 5.5 to 6.5. Optimum temperature for activity was 30 °C and the enzyme had residual activity of greater than 50% during storage for 72 h at 20 °C to 30 °C and for 24 h at 40 °C to 50 °C. Of the substrates tested, activity was greatest with 4-methylcatechol followed by catechol, pyrogallol, and (−)epicatechin. The most effective inhibitors tested were sodium metabisulfite and ascorbic acid.