Affinity purification and characterization of polyphenol oxidase from helianthus tuberosus L.
Abstract
Polyphenol oxidase (PPO) of Jerusalem artichoke (Helianthus Tuberosus L.) tubers was
purified using a Sepharose-4B-L-tyrosine-p-amino benzoic acid affinity gel. Both nativeand SDS-gel electrophoresis analyses of the purified PPO gave a single band (ca. 65 kDa
based on SDS-PAGE), indicating that it is a monomer. The purified PPO showed activity
towards diphenolic and triphenolic substrates but not with the monophenolic substrates,
suggesting that it lacks monophenolase activity. The optimum temperature and pH values
vary between 20-35oC and 5.0-8.0, respectively, depending on the substrate used; for
catechol, the optimum temperature and pH values were found to be 20oC and 7.0,
respectively. The purified enzyme was relatively stable at 40oC but unstable at higher
temperatures. Furthermore, IC50 values for various inhibitors and inhibition modes were
also determined using catechol as a substrate; β-mercaptoethanol showed the strongest
inhibition, followed by 2-mercapto benzothiazol, glutathione, L-cysteine and dithioerythritol,
respectively
Source
Hacettepe Journal of Biology and ChemistryVolume
37Issue
4Collections
- Makale Koleksiyonu [325]
- TR-Dizin İndeksli Yayınlar Koleksiyonu [2292]