PURIFICATION AND PROPERTIES OF POLYPHENOL OXIDASE FROM CABBAGE (BRASSICA-OLERACEA L)
PURIFICATION AND PROPERTIES OF POLYPHENOL OXIDASE FROM CABBAGE (BRASSICA-OLERACEA L)
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DOI：
10.1021/jf00053a005
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发表时间：
1995-05-01
影响因子：
6.1
通讯作者：
TONO, T
中科院分区：
文献类型：
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作者：
FUJITA, S;BINSAARI, N;TONO, T
以间苯三酚为底物纯化了甘蓝中的多酚氧化酶（PPO）。经PAGE和SDS-PAGE分析，纯化后的酶呈均相状态。经凝胶过滤和SDS-PAGE分析，酶的分子量分别约为39000和40000。纯化后的酶仅能氧化间苯三酚（K-m = 6.4 mM）和间苯三酚羧酸等1,3,5-三羟基苯。该酶还具有较强的过氧化物酶（POD）活性。PPO和POD的最适pH值分别为7.6和6.4，在5℃条件下，pH值在6 ~ 11范围内保持活性稳定20 h，具有很高的热稳定性；在100℃下热处理10分钟后，约有40%的PPO和25%的POD活性保持不变。二乙基二硫代氨基甲酸钠和氰化钾显著抑制了这两种活性。MnCl2显著激活PPO活性，但强烈抑制POD活性。
Polyphenol oxidase (PPO) in cabbage (Brassica oleracea L.) was purified using phloroglucinol as substrate. The purified enzyme was found to be of a homogeneous state by PAGE and SDS-PAGE. The molecular weight of the enzyme was estimated to be about 39 000 and 40 000 by gel filtration and SDS-PAGE, respectively. The purified enzyme only oxidized 1,3,5-trihydroxybenzenes such as phloroglucinol (K-m = 6.4 mM) and phloroglucinolcarboxylic acid. The enzyme also had strong peroxidase (POD) activity. The optimal pH values of PPO and POD were 7.6 and 6.4, respectively, and both activities were stable in the pH ranges 6-11 at 5 degrees C for 20 h. Both activities had very high thermal stability; about 40% of the PPO and about 25% of the POD activities remained after heat treatment at 100 degrees C for 10 min. Both activities were markedly inhibited by sodium diethyldithiocarbamate and potassium cyanide. MnCl2 markedly activated PPO activity but strongly inhibited POD activity.