Characterization of polyphenoloxidase (PPO) extracted from 'Jonagored' apple

• Type: Article in International Scientific Journal
• Date: 2001

Authors

Rocha, Ada (Author) FCNAUP; Morais, AMMB (Author) Other

Journal

Title: Food Control

Vol. 12 No. 2

Pages: 85-90

ISSN: 0956-7135

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 78 Citations

Scopus - 86 Citations

Scientific classification

FOS: Medical and Health sciences > Health sciences

CORDIS: Health sciences

Other information

Authenticus ID: P-000-W81

DOI: 10.1016/s0956-7135(00)00026-8

Abstract (EN): Polyphenoloxidase (PPO) was extracted from apple (cv. Jonagored) with addition of 2% PVP and 0.25% Triton X100 to the extraction buffer containing phenolic adsorbents. Experiments were performed to evaluate the affinity and specificity towards several substrates. 'Jonagored' apple PPO was found to have higher specificity (lower K-m) towards L-dopa, 4-methylcatechol and (+) catechin than other phenols tested, but the highest activity level was obtained with p-cresol. The ratio V-max/K-m indicates that p-cresol followed by L-dopa and 4-methylcatechol are the best substrates for 'Jonagored' apple PPO. The enzyme activity showed two pH optima, at 5.0 and 7.5, at room temperature, with the main peak at pH 7.5 and the secondary one at pH 5.0 when catechol was the substrate.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6