化学
多酚氧化酶
儿茶酚
没食子酸
褐变
麸皮
亚硫酸氢钠
抗坏血酸
食品科学
糊粉
基质(水族馆)
色谱法
酶
生物化学
抗氧化剂
有机化学
生物
原材料
过氧化物酶
生态学
作者
Kefu Yu,Wenliang He,Xiao Ma,Zhang Qi,Chunxu Chen,Peiyan Li,Di Wu
出处
期刊:Molecules
[MDPI AG]
日期:2024-03-17
卷期号:29 (6): 1334-1334
标识
DOI:10.3390/molecules29061334
摘要
Currently, little is known about the characteristics of polyphenol oxidase from wheat bran, which is closely linked to the browning of wheat product. The wheat PPO was purified by ammonium sulfate precipitation, DEAE-Sepharose ion-exchange column, and Superdex G-75 chromatography column. Purified wheat PPO activity was 11.05-fold higher, its specific activity was 1365.12 U/mg, and its yield was 8.46%. SDS-PAGE showed that the molecular weight of wheat PPO was approximately 21 kDa. Its optimal pH and temperature were 6.5 and 35 °C for catechol as substrate, respectively. Twelve phenolic substrates from wheat and green tea were used for analyzing the substrate specificity. Wheat PPO showed the highest affinity to catechol due to its maximum Vmax (517.55 U·mL−1·min−1) and low Km (6.36 mM) values. Docking analysis revealed strong affinities between catechol, gallic acid, EGCG, and EC with binding energies of −5.28 kcal/mol, −4.65 kcal/mol, −4.21 kcal/mol, and −5.62 kcal/mol, respectively, for PPO. Sodium sulfite, ascorbic acid, and sodium bisulfite dramatically inhibited wheat PPO activity. Cu2+ and Ca2+ at 10 mM were considered potent activators and inhibitors for wheat PPO, respectively. This report provides a theoretical basis for controlling the enzymatic browning of wheat products fortified with green tea.
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