Isolation and Characterization of Two Phloroglucinol Oxidases from Cabbage (Brassica oleracea L.)

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• 作者：Shuji Fujita ; Nazamid bin Saari ; Mitsuru Maegawa ; Naoki Samura ; Nobuyuki Hayashi ; and Tetsuzo Tono
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：1997
• 出版时间：January 1997
• 年：1997
• 卷：45
• 期：1
• 页码：59 - 63
• 全文大小：117K
• 年卷期：v.45,no.1(January 1997)
• ISSN：1520-5118

文摘

Two isozymes (F-IB and F-II) of phloroglucinol oxidase (PhO) in cabbage(Brassica oleracea L.) werepurified from cabbage. The purified enzymes were found to be in ahomogeneous state bypolyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate(SDS)-PAGE. The molecularweights of F-IB and F-II were estimated to be ~43 000 and 32 000,respectively, by SDS-PAGE.Both purified enzymes only oxidized 1,3,5-trihydroxybenzenes, suchas phloroglucinol and phloroglucinolcarboxylic acid. Both enzymes also had strong peroxidase(POD) activity. The pH optimaof PhO and POD of F-IB were 8.0 and 6.7, respectively, and those ofF-II were 7.4 and 6.7,respectively. Activities of both F-IB and F-II were stable in thepH range 6-11 at 5 C for 20 h,and were markedly inhibited by sodium diethyldithiocarbamate andpotassium cyanide. MnCl₂markedly activated the PhO activity of F-IB and F-II, but stronglyinhibited their POD activity.Keywords: Cabbage (Brassica oleracea L.); polyphenol oxidase;phloroglucinol oxidase; peroxidase;characterization