POLYPHENOLOXIDASE FROM AMASYA APPLE


OKTAY M., KUFREVIOGLU I., KOCACALISKAN İ. , SAKIROGLU H.

JOURNAL OF FOOD SCIENCE, vol.60, no.3, pp.494-496, 1995 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 60 Issue: 3
  • Publication Date: 1995
  • Doi Number: 10.1111/j.1365-2621.1995.tb09810.x
  • Journal Name: JOURNAL OF FOOD SCIENCE
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.494-496
  • Keywords: AMASYA APPLE, POLYPHENOLOXIDASE, ISOZYMES, PHYSICAL STABILITY, PYRUS-COMMUNIS L, GRAPE POLYPHENOLOXIDASE, PARTIAL-PURIFICATION, CATECHOL OXIDASE, PROTEINS, PLANTS, PEACH

Abstract

Polyphenoloxidase (PPO) of Amasya apple was partially purified by (NH4)(2)SO4 precipitation and dialysis. The sample was used for characterization of the PPO. Optimum pH were 7.0, 9.0, 8.6 and 6.6 on substrates catechol, I-methyl catechol, pyrogallol and L-dopa respectively. Catechol was the most suitable for Amasya apple PPO. The optimum temperature for maximum PPO activity was 18 degrees C with catechol. Of seven inhibitors tested, the strongest was L-cysteine. Effectiveness of inhibitors increased in the order: thiourea, glutathione, beta-mercaptoethhanol, sodium cyanide, ascorbic acid, sodium metabisulfide, and L-cysteine. The K-M was 34 mM of catechol. The activation energy with catechol was 107 cal/mol. In electrophoretic separation, three isoenzymes were detected with both catechol and L-dopa substrates.