Spectrophotometric Method for the Determination of Polyphenol Oxidase Activity by Coupling of 4-tert-Butyl-o-Benzoquinone and 4-Amino-N,N-Diethylaniline
作者:
Antonio Rescigno,
Enrico Sanjust,
Gian Franco Pedulli,
Luca Valgimigli,
期刊:
Analytical Letters
(Taylor Available online 1999)
卷期:
Volume 32,
issue 10
页码: 2007-2017
ISSN:0003-2719
年代: 1999
DOI:10.1080/00032719908542948
出版商: Taylor & Francis Group
关键词: Polyphenol oxidase;Catecholase;Spectrophotometric assay
数据来源: Taylor
摘要:
We describe a spectrophotometric analytical method for the detection of polyphenol oxidase activity in an aqueous solution. The assay is based on the coupling reaction between 4-tert-butyl-o-benzoquinone, generated during the enzyme-catalyzed reaction acting on 4-tert-butylcatechol, and the aromatic amine, 4-amino-N,N-diethylaniline to yield a blue adduct (λmax625 nm). This blue adduct exhibited spectral features different from the parent phenol and from theo-quinone. Polyphenol oxidase activities extracted from potatoes, and sunflower seedlings were assayed. The proposed method presents several advantages over the spectrophotometric measurement of 4-tert-butyl-o-benzoquinone. The duration of the linear period was increased, allowing a better determination of its value. The molar extinction coefficient of the blue adduct was higher than that of the 4-tert-butyl-o-benzoquinone; therefore the limitation i8542948 by the comparatively low ɛ for the 4-tert-butyl-o-benzoquinone is overcome. This is of great importance when considering the inertness of the 4-tert-butyl-o-benzoquinone towards some common coupling agents such as 3-methyl-benzothiazolin-2-one hydrazone.
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