Metalloenzyme Research Group and Department of Biotechnology, Chung-Ang University, Anseong 456-756, South Korea.
Appl Microbiol Biotechnol. 2011 Aug;91(4):1173-81. doi: 10.1007/s00253-011-3310-7. Epub 2011 May 12.
A Gram-negative anaerobic microorganism, MRG-1, isolated from human intestine showed high activities of deglycosylation and reduction of daidzin, based on rapid TLC analysis. A rod-shaped strain MRG-1 was identified as a new species showing 91.0% homology to Coprobacillus species, based on 16S rRNA sequence analysis. The strain MRG-1 showed β-glucosidase activity toward daidzin and genistin, and daidzein and genistein were produced, respectively. However, the strain MRG-1 did not react with flavone glycosides, flavanone glycosides, and isoflavone C-glucoside. Besides, MRG-1 showed stereoselective reductase activity to isoflavone, daidzein, genistein, 7-hydroxyisoflavone, and formononetin, resulting in the formation of corresponding R-isoflavanone enantiomers. The new isoflavanones of 7-hydroxyisoflavanone and dihydroformononetin were characterized by NMR, and the absolute configurations of the enantiomers were determined with CD spectroscopy. The kinetic study of the anaerobic biotransformation showed both activities were exceptionally fast compared to the reported conversion by other anaerobic bacteria.
从人肠道中分离到的一种革兰氏阴性厌氧微生物 MRG-1，通过快速 TLC 分析显示出对大豆苷和大豆黄素的高去糖基化和还原活性。基于 16S rRNA 序列分析，MRG-1 被鉴定为一种新的种，与 Coprobacillus 属的同源性为 91.0%。该菌株 MRG-1 对大豆苷和金雀异黄素表现出β-葡萄糖苷酶活性，分别产生大豆苷元和染料木素。然而，该菌株 MRG-1 与黄酮糖苷、黄烷酮糖苷和异黄酮 C-糖苷没有反应。此外，MRG-1 对异黄酮、大豆苷、染料木素、7-羟基异黄酮和芒柄花素表现出立体选择性还原酶活性，导致相应的 R-异黄烷酮对映体的形成。新的 7-羟基异黄烷酮和二氢芒柄花素通过 NMR 进行了表征，并通过 CD 光谱确定了对映体的绝对构型。厌氧生物转化的动力学研究表明，与其他厌氧细菌报道的转化率相比，这两种活性都非常快。
