• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.35-36
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• 2006

• Journal of Microbiology and Biotechnology
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• 제33권12호
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• pp.1606-1614
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• 2023

Biochemical gut metabolism of dietary bioactive compounds is of great significance in elucidating health-related issues at the molecular level. In this study, a human gut bacterium cleaving C-C glycosidic bond was screened from puerarin conversion to daidzein, and a new, gram-positive C-glycoside-deglycosylating strain, Dorea sp. MRG-IFC3, was isolated from human fecal sample under anaerobic conditions. Though MRG-IFC3 biotransformed isoflavone C-glycoside, it could not metabolize other C-glycosides, such as vitexin, bergenin, and aloin. As evident from the production of the corresponding aglycons from various 7-O-glucosides, MRG-IFC3 strain also showed 7-O-glycoside cleavage activity; however, flavone 3-O-glucoside icariside II was not metabolized. In addition, for mechanism study, C-glycosyl bond cleavage of puerarin by MRG-IFC3 strain was performed in D₂O GAM medium. The complete deuterium enrichment on C-8 position of daidzein was confirmed by ¹H NMR spectroscopy, and the result clearly proved for the first time that daidzein is produced from puerarin. Two possible reaction intermediates, the quinoids and 8-dehydrodaidzein anion, were proposed for the production of daidzein-8d. These results will provide the basis for the mechanism study of stable C-glycosidic bond cleavage at the molecular level.

• Journal of Applied Biological Chemistry
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• 제57권3호
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• pp.211-218
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• 2014

Polymethoxyflavones (PMFs) are a group of polymethoxylated bioactive flavones with diverse biological activities, including anticancer, anti-inflammatory, antibacterial, and antiviral activities. PMFs are found from various plants such as orange, tangerine, and krachaidum. To establish the simple quantitative analytical methods for PMFs, chromatographic analysis was applied to the selected krachaidum foods because krachaidum contains diverse PMFs compared to other PMF-containing foods. Krachaidum is the rhizome of Kaempferia parviflora, and many commercial krachaidum products, such as tea, juice and wine, are commercially available and consumed as health functional foods in Asian countries. Apart from the claimed health promoting benefits, reliable quality assurance and legal guideline for the registration of these products are not available yet. Twelve PMFs were analyzed from the commercial krachaidum foods by GC-FID and HPLC-DAD. No single chromatographic method could not analyze 12 PMFs simultaneously. HPLC-DAD method was found more sensitive to detect PMFs. Based on our analysis data, we proposed 5,7-dimethoxyflaone and 5,7,4'-trimethoxyflavone as index components for the food products.

• 한국균학회지
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• 제30권2호
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• pp.113-118
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• 2002

S. rugosoannulata의 배양액으로부터 4단계를 거쳐 분자량이 54 kDa인 CMCase를 분리 정제하였다. 이 효소는 pH 4.0에서 최대의 활성을 보여주는 acidic CMCase로 $40^{\circ}C$에서 최대활성을 나타냈다. EDTA에 의해 활성이 저해되는 것으로 보아 metalloenzyme으로 추정되며 1,10-phenanthroline과 KCN 및 L-cystein 등의 저해제에 효소활성이 크게 감소하였으며, $AgNO_{3},\;MgSO_{4},\;KCl$등의 금속염에서는 효소활성이 증가되었으나, $ZnSO_{4},\;BaCl_{2},\;CaCl_{2}$ 등에서는 효소활성이 저해되었다.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1270-1275
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• 2024

Human gut bacterium Dorea sp. MRG-IFC3 is unique in that it is capable of metabolizing puerarin, an isoflavone C-glycoside, whereas it shows broad substrate glycosidase activity for the various flavonoid O-glycosides. To address the question on the substrate specificity, as well as biochemical characteristics, cell-free biotransformation of flavonoid glycosides was performed under various conditions. The results showed that there are two different enzyme systems responsible for the metabolism of flavonoid C-glycosides and O-glycosides in the MRG-IFC3 strain. The system responsible for the conversion of puerarin was inducible and comprised of two enzymes. One enzyme oxidizes puerarin to 3"-oxo-puerarin and the other enzyme converts 3"-oxo-puearin to daidzein. The second enzyme was only active toward 3"-oxo-puerarin. The activity of puerarin conversion to daidzein was enhanced in the presence of Mn²⁺ and NAD⁺. It was concluded that the puerarin C-deglycosylation by Dorea sp. MRG-IFC3 possibly adopts the same biochemical mechanism as the strain PUE, a species of Dorea longicatena.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1994년도 한국생물과학협회 학술발표대회
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• pp.194.2-194
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• 1994

No Abstract, See Full Text

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.447-451
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• 2022

Phytoestrogenic S-equol production in human gut exclusively depends on the biotransformation of daidzein to dihydrodaidzein (DHD). With a growing demand for the DHD enriched biomaterials, the commercial soybean hypocotyl extract (SHE) was chosen as a substrate for the microbial DHD production by human gut bacterium MRG-1, anaerobic DHD producer. To optimize the production of DHD, anaerobic fermentation conditions, including sterilization time, growth stage of inoculum, and growth media, were investigated. Maximum DHD production (1.2 g/L) was achieved after 48 h incubation when 1% (w/v) of SHE in the 20-min-sterilized Gifu Anaeboic Medium media was inoculated with OD₆₀₀ 0.3-0.4 of MRG-1. This is the first report that crude soy biomaterial, instead of pure compounds, such as daidzin and daidzein, is utilized for the production of the DHD enriched biomaterial.

• KSBB Journal
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• 제18권6호
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• pp.517-521
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• 2003

본 연구에서는 절대적 호기성인 Vitreoscilla가 지닌 FeSOD의 특성을 밝히고자 paraquat와 iron을 사용하여 실험하였다. Vitreoscilla에서 FeSOD의 활성도는 초산화 음이온을 생성하는 paraquat에 대해 커다란 영향 없이 일정하게 발현되었다. 이 결과는 Vitreoscilla는 호기적인 물질대사 동안 생성되어지는 초산화 음이온에 대해 방어할 수 있을 만큼 충분한 FeSOD를 평상시 지니고 있음을 의미한다. 또한 다른 요소에 의한 FeSOD의 발현 가능성이 고려되어졌다. 보조 인자인 Fe 를 처리한 결과 활성도가 증가됨을 알 수 있었다. 이는 CN-resistant respiration을 증가시키는 초산화 음이온에 대한 조절 기작과는 달리 apoenzyme 상태가 보조 인자인 금속 이온 (Fe)에 의해 holoenzyme 상태로 전환되었음을 의미한다. PQ와 Fe를 함께 처리하였을 경우, FeSOD의 증가는 PQ에 의해서 생성된 초산화 음이온에 의해 apo 상태에서 hole 상태로 FeSOD의 활성이 증진되는 synergism effect로 설명되어진다. 결론적으로 metalloenzyme인 SOD의 경우는 이런 전환이 활성 속도를 제한하거나 조절할 수도 있는 posttranslational 수준의 조절 기작이 존재함을 알 수 있었다.

• 한국균학회지
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• 제32권2호
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• pp.125-129
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• 2004

섬유소분해효소(CMCase)를 산업적으로 이용하기 위한 기초자료를 제공하고자 섬유소분해능이 우수한 L. japonicus로부터 CMCase를 분리 정제하였다. L. japonicus의 배양액으로부터 4단계를 거쳐 분자량이 42 kDa인 CMCase를 분리 정제하였다. 이 효소는 pH 6.0에서 최적의 활성을 보여주는 acidic CMCase로서 $30^{\circ}C$에서 최대 활성을 나타냈다. EDTA에 의해 활성이 저해되는 것으로 보아 metalloenzyme으로 추정되며, SDS에 의해 저해되는 것으로 보아 S-S기를 갖고 있는 효소로 판단된다. $Al_{2}(SO_{4})_{3}$와 $BaCl_{2}$에서는 효소 활성이 높았으나 그 이외의 금속염에서는 효소 활성이 낮았다.

• 한국균학회지
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• 제33권2호
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• pp.75-80
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• 2005

섬유소분해능이 우수한 L. roseoalbus로부터 분리 정제한 CMCase의 활용에 대한 기초적인 자료를 제공하고자 실험하여 L. roseoalbus의 배양액으로부터 4단계를 거쳐 분자량이 28.5 kDa인 CMCase를 분리 정제하였다. 이 효소는 pH 4.0에서 최적의 활성을 보여주는 acidic CMCase로 $30^{\circ}C$에서 최대 활성을 나타냈다. EDTA에 의해 활성이 저해되는 것으로 보아 metalloenzyme으로 추정되며, PMSF에 의해 저해되는 것으로 보아 serine 잔기를 갖고 있는 효소로 판단된다. $Al_{2}(SO_{4})_{3}$와 $FeSO_{4}$에서는 효소활성이 높았으나 $CaCl_{2}$와 $Na_{2}MoO_{4}$에서는 효소 활성이 낮았다.