文章基本信息

标题：Melissa officinalis L. subsp. officinalis (lemon balm)
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作者：Doğan S. ; Ayyildiz Y. ; Doğan M. 等
期刊名称：Czech Journal of Food Sciences
印刷版ISSN：1212-1800
电子版ISSN：1805-9317
出版年度：2013
卷号：31
期号：2
页码：156-165
DOI：10.17221/288/2011-CJFS
出版社：Czech Academy of Agricultural Sciences
摘要：Polyphenol oxidase (PPO) from Melissa officinalis L. subsp. officinalis (lemon balm) was partially purified by ammonium sulphate precipitation and dialysis; and then it was characterised in detail in terms of pH and temperature optima, thermal stability, kinetic parameters, and inhibition properties. Based on experimental results, it was found out that ( i ) the optimum pH and temperature values of PPO were 6.5, 4.0, and 8.5 and 40, 50, and 60°C for catechol, 4-methylcatechol and pyrogallol substrates, respectively; ( ii ) the best substrate was pyrogallol due to the highest V _max/ K_m value, followed by catechol and 4-methylcatechol; ( iii ) enzyme activity decreased due to heat denaturation of the enzyme with increasing temperature and inactivation time for all substrates; ( vi ) gallic acid and l-glutamic acid did not inhibit PPO; and ( v ) the most effective inhibitor was glutathione. Furthermore, the phenolic and protein contents of lemon balm extract were also determined according to the Folin-Ciocalteu and Bradford methods, respectively.
关键词：lemon balm; protein; enzyme kinetics; inhibition