Purification and Characterization of Polyphenol Oxidase from Cauliflower (Brassica oleracea L.)

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• 作者：Andi Nur Faidah Rahman ; Mayumi Ohta ; Kazuya Nakatani ; Nobuyuki Hayashi ; Shuji Fujita
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：April 11, 2012
• 年：2012
• 卷：60
• 期：14
• 页码：3673-3678
• 全文大小：259K
• 年卷期：v.60,no.14(April 11, 2012)
• ISSN：1520-5118

文摘

Polyphenol oxidase (PPO) of cauliflower was purified to 282-fold with a recovery rate of 8.1%, using phloroglucinol as a substrate. The enzyme appeared as a single band on sodium dodecyl sulfate鈥損olyacrylamide gel electrophoresis (SDS鈥揚AGE). The estimated molecular weight of the enzyme was 60 and 54 kDa by SDS鈥揚AGE and gel filtration, respectively. The purified enzyme, called phloroglucinol oxidase (PhO), oxidized phloroglucinol (K_m = 3.3 mM) and phloroglucinolcarboxylic acid. The enzyme also had peroxidase (POD) activity. At the final step, the activity of purified cauliflower POD was 110-fold with a recovery rate of 3.2%. The PhO and POD showed the highest activity at pH 8.0 and 4.0 and were stable in the pH range of 3.0鈥?1.0 and 5.0鈥?.0 at 5 掳C for 20 h, respectively. The optimum temperature was 55 掳C for PhO and 20 掳C for POD. The most effective inhibitor for PhO was sodium diethyldithiocarbamate at 10 mM (IC₅₀ = 0.64 and K_i = 0.15 mM), and the most effective inhibitor for POD was potassium cyanide at 1.0 mM (IC₅₀ = 0.03 and K_i = 29 渭M).

Keywords:

Cauliflower; polyphenol oxidase; phloroglucinol oxidase; peroxidase; purification; characterization