• Biomolecules & Therapeutics
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• 제6권3호
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• pp.242-246
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• 1998

The inhibitory activities of Amberlite active fraction, which was obtained from methanol soluble fraction of freeze dried slikworm urine, on the rat intestinal glycosidase-catalyzed enzymatic reaction were examined in in viro and in vivo experiments. Amberlite active fraction showed significant inhibitory effects on the hydrolysis of o-glycosidic bond, especially $\alpha$-1,4 bond. On the other hand, the inhibition on the hydrolysis of $\beta$-glycosidic bond was very weak. Oral administration of Amberlite active fraction resulted in a dose-dependent decrease in the blood glucose after an oral maltose load, and postprandial hyperglycemia in carbohydrate-loaded mice was suppressed by Amberlite active fraction at 60 mgHg in decreasing order of maltose, starch, sucrose and lactose. 60 mg/kg of Amberlite active fraction lowered the blood glucose level markedly after 18, 35, and 60 min after an oral maltose load and the antihyperglycemic activity was maintained upto 90 min. In alloxan-induced hyperglycemic mice, Amberlite active fraction at a dose of 100 mg/kg also significantly lowered blood glucose after an oral maltose load, and its efficacy was almost equivalent to that of acarbowe.

• 한국미생물·생명공학회지
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• 제30권2호
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• pp.151-156
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• 2002

내열성 $\beta$-glycosidase 효소를 생성하는 균주를 분리하기 위해서 일본의 Atagawa 온천지역에서 시료를 채취하였다. 조효소액이 $70^{\circ}C$에서 4시간 동안 $\beta$-glycosidase활성을 유지하는 KNOUC 202를 선발하여 분리, 동정하였다. 선발된 KNOUC 202는 호기성으로 그람음성 간균이며, 포자를 형성하지 않으며, 운동성이 없으며, carotenoid를 생성하고, catalase, oxidase 양성으로 나타났으며, 최적 성장온도는 $70~72^{\circ}C$이고, 최적 pH는 7.0~7.2이었으며, NaCl 3% 농도에서 성장하였다. 세포내 지방산의 주성분은 iso-15:0과 iso-17:0이었다. KNOUC 202의 16S rRNA sequence는 Thermus thermophilus ATCC 27635(HB8)와 유사도가 99.9% 이었다. 따라서 형태학적, 이화학적, 생화학적 특성, 지방산조성 및 16S rRNA sequence 분석결과에 근거하여 KNOUC 202를 Thermus thermophilus로 동정하였다.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.287-294
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• 2008

Three amino acid residues (His119, Glu164, and Glu338) in the active site of Thermus caldophilus GK24 ${\beta}$-glycosidase (Tca ${\beta}$-glycosidase), a family 1 glycosyl hydrolase, were mutated by site-directed mutagenesis. To verify the key catalytic residues, Glu164 and Glu338 were changed to Gly and Gln, respectively. The E164G mutation resulted in drastic reductions of both ${\beta}$-galactosidase and ${\beta}$-glucosidase activities, and the E338Q mutation caused complete loss of activity, confirming that the two residues are essential for the reaction process of glycosidic linkage hydrolysis. To investigate the role of His119 in substrate binding and enzyme activity, the residue was substituted with Gly. The H119G mutant showed 53-fold reduced activity on 5mM p-nitrophenyl ${\beta}$-D-galactopyranoside, when compared with the wild type; however, both the wild-type and mutant enzymes showed similar activity on 5mM p-nitrophenyl ${\beta}$-D-glucopyranoside at $75^{\circ}C$. Kinetic analysis with p-nitrophenyl ${\beta}$-D-galactopyranoside revealed that the $k_{cat}$ value of the H119G mutant was 76.3-fold lower than that of the wild type, but the $K_m$ of the mutant was 15.3-fold higher than that of the wild type owing to the much lower affinity of the mutant. Thus, the catalytic efficiency $(k_{cat}/K_m)$ of the mutant decreased to 0.08% to that of the wild type. The $k_{cat}$ value of the H119G mutant for p-nitrophenyl ${\beta}$-D-glucopyranoside was 5.l-fold higher than that of the wild type, but the catalytic efficiency of the mutant was 2.5% of that of the wild type. The H119G mutation gave rise to changes in optima pH (from 5.5-6.5 to 5.5) and temperature (from $90^{\circ}C\;to\;80-85^{\circ}C$). This difference of temperature optima originated in the decrease of H119G's thermostability. These results indicate that His119 is a crucial residue in ${\beta}$-galactosidase and ${\beta}$-glucosidase activities and also influences the enzyme's substrate binding affinity and thermostability.

• 한국식품저장유통학회지
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• 제8권1호
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• pp.66-73
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• 2001

본 연구에서는 복숭아 '미백도', '대구보' 및 '유명' 과실의 발육단계별로 과실의 경도, 세포벽성분 및 g1ycisidase 활성의 변화를 조사함으로써 수확후의 저장중 과실에서와 같이 발육중인 과실의 연화에서 도 $\beta$-galactosidase가 중요한 역할을 하는지 알고자 하였다. 조사시기는 5월 13일, 6월 16일, 7월 16일, 8월 5일이었으며, 수확기가 늦은 '유명'은 8월 28일에 한번 더 조사하였다. Total sugar와 비섬유성 중성당의 함량은 각 품종의 세포벽물질을 증류수, 0.05M CDTA 0.05M $Na_2$CO$_3$, 4% KOH, 2.4% KOH로 차례로 분획하여 조사하였다. 과실의 발육에 따라 경도는 세 품종 모두에서 감소하였으며, '유명' 과실의 경도는 모든 발육단계에서 '미백도'와 '대구보'보다 높았다. 발육단계에 따른 각 분획별 total sugar의 함량 변화는 품종간에 뚜렷한 차이가 없었다. 세 품종의 세포벽 물질과 각 분획중의 주요 중성당은 arabinose와 galactose였다. '미백도'와 '대구보'의 수확일인 8월 5일의 증류수 가용성 분획의 rhamnose의 mol % 변화는 품종별 경도 변화와 상관관계가 있었다. 가용성 $\beta$-galactosidase의 활성은 세 품종 모두에서 파실 발육초기에는 높았으나 초기 이후에는 매우 낮은 수준이었다. 세포벽결합형 $\beta$-galactosidase는 세 품종 모두에서 발육초기에 높았던 활성이 수확기가지 계속적으로 감소하였다. 다른 glycosidase의 활성들도 품종간에 뚜렷한 차이를 보이지는 않았다.

• 한국당과학회:학술대회논문집
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• 한국당과학회 2006년도 제1회 연례학술대회
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• pp.59-59
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• 2006

• Journal of Microbiology and Biotechnology
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• 제20권6호
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• pp.1011-1017
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• 2010

A novel dioscin-glycosidase that specifically hydrolyzes multi-glycosides, such as 3-O-${\alpha}$-L-($1{\to}4$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, and ${\beta}$-D-glucoside, on diosgenin was isolated from the Absidia sp.d38 strain, purified, and characterized. The molecular mass of the new dioscin-glycosidase is about 55 kDa based on SDS-PAGE. The dioscin-glycosidase gradually hydrolyzes either 3-O-${\alpha}$-L-($1{\to}4$)-Rha or 3-O-${\alpha}$-L-($1{\to}2$)-Rha from dioscin into 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin, further rapidly hydrolyzes the other ${\alpha}$-L-Rha from 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin into the main intermediate products of 3-O-${\beta}$-D-Glc-diosgenin, and subsequently hydrolyzes these intermediate products into aglycone as the final product. The enzyme also gradually hydrolyzes 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, and ${\beta}$-D-glucoside from [3-O-${\alpha}$-L-($1{\to}4$)-Ara, 3-O-${\alpha}$-L-($1{\to}4$)-Rha]-${\beta}$-D-Glc-diosgenin into diosgenin as the final product, exhibiting significant differences from previously reported glycosidases. The optimal temperature and pH for the new dioscin-glycosidase is $40^{\circ}C$ and 5.0, respectively. Whereas the activity of the new dioscin-glycosidase was not affected by $Na^+$, $K^+$, and $Mg^{2+}$ ions, it was significantly inhibited by $Cu^{2+}$ and $Hg^{2+}$ ions, and slightly affected by $Ca^{2+}$ ions.

• 한국잠사곤충학회지
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• 제48권1호
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• pp.25-27
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• 2006

누에장려품종 중 혈당강하제 개발에 적합한 품종 결정을 위하여 DNJ 함량을 정량한 결과, 봄에 사육한 금옥잠이 5.45 mg/gDW으로 DNJ 함량이 가장 높았다. 또한 누에 유전자원 원종 66품종의 DNJ 함량을 결정한 결과, 품종간 DNJ 함량 차이가 매우 큰 것으로 밝혀져, 혈당 강하제용 누에 육종시 기초자료가 될 수 있으며, 또한 DNJ 함량이 낮은 품종은 DNJ 축적 기작 연구에 많은 도움이 될 것으로 사료된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.721-724
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• 2000

재조합 단백질 생산에서 문제가 되고 있는 번역 후 과정인 glycosylation 을 in vitro 상에서 수행하였다. 원핵생물 시스템에서 재조합 단백질을 생산하고, 이후 효소를 이용하여 올리고당을 붙여 원래의 당단백질과 유사한 단백질을 생산하는 것이 산업적으로 경쟁력을 가질 수 있으므로 이를 위하여 glucose oxidase와 fetuin을 모델 당단백질로, 가수분해 효소인 peptide-N-glycosidase F 의 역반응 활성을 이용하여 glycosylation 을 시도하였다. 역가수분해로의 평형 이동을 위하여 그 기질인 올리고당과 암모니아를 과량 첨가하고, 반응 온도를 높였다. Glucose oxidase의 경우에는 denaturation 했을 때 완전한 deglycosylation 이 일어났지만, fetuin의 경우에는 그렇지 못했다. Glucose oxidase 의 glycosylation 은 수용액상에서는 불가능 했지만 acetone 을 media로 사용하여 $50^{\circ}C$에서 4 시간동안 반응시켰을 때 SDS-PAGE 분석 결과 reglycosylation이 일어나 단백질 밴드가 위로 올라감을 관찰할 수 있었다.

• 약학회지
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• 제42권6호
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• pp.613-620
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• 1998

Antidiabetic activity of Mori folium ethanol soluble fraction (MFESF) was examined in db/db mice, which is a spontaneously hyperglycemic, hyperinsulinemic and obese animal model . 500 and 1000mg/kg dose for MFFSF (designated by SY 500 and SY 1000, respectively) and 5mg/kg dose for acarbose were administered for 6 weeks. Body weight gain, fasting and non-fasting serum glucose, glycated hemoglobin and triglyceride were all reduced dose dependently when compared between db/db control group and MFESF treated group. At 11th and 13th week after birth, MFESF increased an insulin secretion which may result in lowering serum glucose level. Total activities of sucrase and maltase in SY 500 treated group were decreased when compared to db/db control. On the other hand, those in SY 1000 and acarbose treated groups were increased. This result may suggest that proteins for sucrase and maltase were compensatorily induced due to significant inhibition of glycosidase-catalyzed reaction at doses administered in this study.

• Archives of Pharmacal Research
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• 제21권1호
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• pp.17-23
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• 1998

Flavonoid glycosides were metabolized to phenolic acids via aglycones by human intestinal microflora producing ${\alpha}$-rhamnosidase, exo-${\beta}$-glucosidase, endo- ${\beta}$-glucosidase and/or ${\beta}$-glucuronidase. Rutin, hesperidin, naringin and poncirin were transformed to their aglycones by the bacteria producing ${\alpha}$-rhamnosidase and ${\beta}$-glucosidase or endo- ${\beta}$-glucosidase, and baicatin, puerarin and daidzin were transformed to their aglycones by the bacteria producing ${\beta}$glucuronidase, C-glycosidase and ${\beta}$-glycosidase, respectively. Anti-platelet activity and cytotoxicity of the metabolites of flavonoid glycosides by human intestinal bacteria were more effective than those of the parental compounds. 3,4-Dihydroxyphenylacetic acid and 4-hydroxyl-phenylacetic acid were more effective than rutin and quercetin on anti-platelet aggregation activity. 2,4,6-Trihydroxybenzaidehyde, quercetin and ponciretin were more effective than rutin and ponciretin on the cytotoxicity for tumor cell lines. We insist that these flavonoid glycosides should be natural prodrugs.