Purification and characterization of novel isoforms of the polyphenol oxidase from Malus domestica fruit pulp

PLoS One. 2023 Aug 25;18(8):e0276041. doi: 10.1371/journal.pone.0276041. eCollection 2023.

Abstract

Polyphenol oxidases (PPOs), belong to the group of oxidoreductases that are copper containing enzymes and are responsible for plant browning. PPOs are extensively distributed in plant kingdom and can oxidize wide range of aromatic compounds of industrial importance. The aim of this study was purification and characterization of PPO isoforms from the fruit pulp of Golden delicious apple. High performance liquid chromatography was used to purify the two novel isoforms of PPO and further their molecular weights (45 and 28 kDa) were determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified isoforms have optimum pH (6.5), optimum temperature (40°C), the Vmax (4.45 μM/min) and Km (74.21 mM) with catechol substrate. The N-terminal microsequences of both PPO isoforms were determined using a pulse liquid protein sequencer and found to be AKITFHG (28 kDa) and APGGG (45 kDa). Polyphenol oxidases are efficiently used in the pharmaceutical, paper and pulp, textiles and food industries. Recently, the PPOs have been used for bioremediation and in the development of biosensors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anacardiaceae*
  • Catechol Oxidase
  • Fruit
  • Malus*
  • Polyphenols
  • Protein Isoforms

Substances

  • Catechol Oxidase
  • Protein Isoforms
  • Polyphenols

Grants and funding

This study was supported by the grants from Higher Education Commission of Pakistan through project (HEC NRPU-10406) funded to Dr. Sheeraz Ahmad. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.