Preventing inhibition of tyrosinase with modified electrodes

Narli I., Kiralp S., Toppare L.

ANALYTICA CHIMICA ACTA, vol.572, no.1, pp.25-31, 2006 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 572 Issue: 1
  • Publication Date: 2006
  • Doi Number: 10.1016/j.aca.2006.04.088
  • Journal Name: ANALYTICA CHIMICA ACTA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.25-31
  • Keywords: enzyme, tyrosinase, biosensor, inhibition, immobilization, wine, CONDUCTING POLYMER MATRICES, POLYPHENOL OXIDASE, PHENOLIC-COMPOUNDS, ENZYME ELECTRODES, GLUCOSE-OXIDASE, SPECTROPHOTOMETRIC METHOD, COMPETITIVE-INHIBITION, CARBOXYLIC-ACIDS, RED WINES, IMMOBILIZATION
  • Middle East Technical University Affiliated: Yes

Abstract

Wines, especially red wines, contain numerous biologically active compounds, the most important of which are polyphenols, whose nutritional importance is attributed to their antioxidant power. Because of this, the detection of the amount of phenolic compounds in red wines becomes extremely important. However, using free enzyme in the determination of phenolic compounds in wines cannot reflect the actual values since there are also naturally found inhibitors in red wines. In this study, benzoic acid, cinnamic acid, and sorbic acid were utilized to understand the behavior of immobilized polyphenol oxidase in the conducting polymer matrices toward inhibition. Cinnamic acid was found to be the most powerful inhibitor for both free and immobilized enzyme in copolymer matrix of poly(terephthalic acid bis-(2-thiophen-3-yl-ethyl) ester) (PTATE) with polypyrrole (PPy). In the case of immobilized enzyme in PPy matrix, it was observed that sorbic acid is a stronger inhibitor than cinnamic acid. The inhibitory effects of these inhibitors on PPO were compared with respect to both the structural differences of inhibitors and conducting polymer matrices. (c) 2006 Elsevier B.V. All rights reserved.