Inhibition kinetics of polyphenol oxidase by glutamic acid

• Published in: European food research & technology 2007-05, Vol.225 (1), p.67-73, Article 67
• Main Authors: Doğan, Serap, Turan, Pınar, Doğan, Mehmet, Alkan, Mahir, Arslan, Oktay
• Format: Article
• Language: English
• Subjects: Acids; Aroma and flavouring agent industries; Biological and medical sciences; Catechol; catechol oxidase; Food industries; Food science; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Glutamic acid; Inhibition; Inhibitors; Mushrooms; Ocimum basilicum; Ocimum basilicum L; Polyphenol oxidase; Pyrogallol; Sodium; Sodium azide; Sodium azides; Substrate inhibition; Substrates
• ISSN: 1438-2377; 1438-2385
• DOI: 10.1007/s00217-006-0383-0

The inhibition of polyphenol oxidase (PPO) by glutamic acid was investigated. Application of different concentrations of glutamic acid to mushroom solution and Ocimum basilicum L. extract showed that glutamic acid appeared to be an effective browning inhibitor. Glutamic acid showed uncompetitive inhibition for mushroom and Ocimum basilicum L. polyphenol oxidases using 4-methylcatechol as a substrate, for mushroom PPO using catechol as a substrate and for Ocimum basilicum L. polyphenol oxidase using pyrogallol as a substrate; mixed-type inhibition for mushroom polyphenol oxidase using pyrogallol as a substrate; and non-competitive inhibition for Ocimum basilicum L. polyphenol oxidase using catechol as a substrate. Furthermore, sodium azide was used as an inhibitor for comparison with the inhibition potency of glutamic acid. It was found that glutamic acid was a more power inhibitor than sodium azide. The type of inhibition observed depended on the substrate, inhibitor and enzyme source used.