• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.217-221
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• 2002

dTDP-D-glucose 4,6-dehydratase (TDPDH) catalyzes the conversion of dTDP-D-glucose to dTDP-4-keto-6-deoxy-D-glucose, and requires $NAD^＋$ as a coenzyme for its catalytic activity. The dTDP-D-glucose 4,6-dehydratase from Streptomyces antibioticus $Tu{\ddot}99$ tightly binds $NAD^＋$ [19]. In order to determine the role of lysine-148 in the $NAD^＋$ binding, the lysine of the dTDP-D-glucose 4,6-dehydratase from Streptomyces antibioticus $Tu{\ddot}99$ was mutated to various amino acids by site-directed mutagenesis. The catalytic activity of the four mutated enzymes of TDPDH did not recover after addition of $NAD^＋$ . However, the activity of K159A, the mutated enzyme of UDP-D-glucose 4-epimerase (UDPE), recovered after the addition of $NAD^＋$ [15]. Although dTDP-glucose 4,6-dehydratase, and UDP-galactose (glucose) 4-epimerase are members of the short-chain dehydrogenase/reductase SDR family and the lysine-148 of TDPDH was highly conserved as in UDPE (Lys-159), the function of the lysine-148 of TDPDH was different from that of UDPE. The mutated enzymes showed that the lysine-148 of the dTDP-D-glucose 4,6-dehydratase played no role in the $NAD^＋$ binding. Accordingly, it is suggested that the lysine-148 of the dTDP-D-glucose 4,6-dehydratase is involved in the folding of TDPDH.

• 한국식품영양학회지
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• 제15권2호
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• pp.126-130
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• 2002

고온성이며 호알칼리성인 Bacillus sp. TA-11이 생성하는 Invertase의 생합성 조절 기작을 규명하고자 먼저 이들의 유도와 억제에 관하여 검토하였다. Invertase는 10mM sucrose을 함유한 생합성 조절배지에서 3시간에 효율적으로 유도되었고 glucose는 sucrose에 의한 invertase 유도를 inducer exclusion 방식으로 억제시켰다. CAMP의 첨가로 glucose에 의한 catabolic repression이 다소 줄어들었다.

• 한국미생물·생명공학회지
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• 제36권1호
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• pp.61-66
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• 2008

Flask 배양으로 기본 유청 배지MSM를 배지로 하고 첨가한 각 탄소원의 PS-7생산 효과를 살펴보면 fructose, glucose와 sucrose의 첨가가 PS-7의 생산을 다른 당에 비해 향상시킴을 알 수 있었다. 그러나 galactose의 경우 첨가량이 증가될수록 오히려 PS-7의 생산량이 감소되는 경향을 나타내었다. 여러 가지 배양 변수를 고려한 결과 glucose씨 첨가가 최적임을 확인하였다. 5L 발효조에 의한 PS-7 생산의 경우 유청과 glucose를 함께 첨가한 것이 유청과 glucose만을 배지의 탄소원으로 사용했을 때 보다 PS-7의 생산량이 월등히 향상되는 것을 알 수 있었으며, 유청 1%와 glucose 1%배지의 경우 PS-7생산량이 3 g/L를 생산하였다. 유청 1%와 glucose 2%배지의 경우 4 g/L의 PS-7의 생산하였으나 잔당량이 $30{\sim}40%$가 남아 생산효율(yield)면에서는 떨어짐을 알 수 있었다. 배지내 Glucose농도 변화에 따른 점성(viscosity)의 변화는 PS-7의 생산량의 변화와 비슷한 패턴을 보이지만 분자량 증대에 따른 점도의 증가는 훨씬 높게 나타났다. 본 실험의 결과 일반적으로 C/N ratio가 다당류인 PS-7생산에 중요한 역할을 하고 있으며, 유청 1%+glucose 1% 배지를 사용할 때 높은 점도와 수율의 PS-7을 얻을 수 있는 최적 배지임을 알 수 있었다.

• Reproductive and Developmental Biology
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• 제28권4호
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• pp.227-233
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• 2004

This study was conducted to investigate the effect of various addition and exclusion time of glucose (Control: no addition, A: 24～72 h, B: 24～48 h, C: 48～72 h, D: 0～72 h, E: 0～48 h, F: 0～24 h and 48～72 h, G: 0～24 h) on embryonic developmental capacity of 2-cell embryos in mice. Developed blastocysts were assessed for mean cell number by differential staining. The zona-intact blastocyst (ZiB) rates were higher (p<0.05) in group B than control. However, the zona-escape blastocyst (ZeB) rates were not significantly different in all groups. At 72 h, total blastocyst (ZiB + ZeB) formation rates were not significantly different in all groups. The mean cell number was not significantly different among all groups. The inner cell mass (ICM) cell number was higher (p<0.05) in group F than control, group A, B and G. The trophectoderm (TE) cell number was higher (p<0.05) in control than group A and D. The %ICM was higher (p<0.05) in group C, D and F than control. The ICM : TE ratio was not significantly different in all groups. Between control and glucose group, no significant difference was observed in the total blastocysts (ZiB + ZeB) formation rates. Also, no significant difference was observed in the mean cell number, ICM cell number and ICM : TE ratio. However the TE cell number was higher (p<0.05) in control than glucose group and %ICM was higher (p<0.05) in glucose group than control. In conclusion, glucose added in culture medium was not inhibitory on blastocyst formation but glucose added for 48 ～72 h in culture medium increases %ICM of blastocysts in mice.

• 한국식품과학회지
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• 제31권2호
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• pp.416-420
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• 1999

육계와 돼지의 혈장에서 포도당과 lysine이 축합하여 갈색의 물질을 생성하는 Maillard 반응을 억제시키기 위하여 혈장에 GOD 5 또는 10 units/g이나 제빵용 효모(0.3% w/w)를 첨가하여 탈당시켰다. GOD와 제빵용 효모의 첨가가 혈장 포도당 함량과 pH 변화에 미치는 영향을 조사했다. 초기 닭과 돼지 혈장의 평균 포도당 농도는 각각 $150\;mg/100\;cm^{3}$과 $143\;mg/100\;cm^{3}$이었다. GOD나 효모를 첨가한 혈장의 포도당 농도는 시간이 지남에 따라 감소되었다. 효모를 이용한 경우, 육계와 돼지의 혈장 포도당이 거의 없어지는데는 약 4시간 정도 걸렸다. 효모가 GOD 보다 혈장 포도당을 빨리 감소시켰고 GOD의 농도 10 units/g이 5 units/g보다 효과적이었다. 혈장 포도당을 제거함으로써 Maillard반응의 억제가 가능하리라 여겨진다. 혈장 포도당의 감소에 따라 pH도 같이 감소했다가 포도당 양이 안정된 후에는 pH 값이 약간 상승했다. 혈장의 pH를 측정함으로써 혈장의 탈당 정도를 간접적으로 알 수 있었다.

• 한국미생물·생명공학회지
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• 제24권4호
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• pp.485-492
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• 1996

myo-Inositol, a growth factor for Saccharomyces cerevisiae (S. cerevisiae), has been known to be incorporated into phosphatidylinositol (PI), which is a kind of phospholipid in the cell membrane, by a membrane-associated PI-synthesizing enzyme. The deficiency of myo-inositol in S. cerevisiae adversely affected the membrane structure and function. On the basis of biochemical functions of myo-inositol, the effect of deficiency of myo-inositol on the aerobic glucose metabolism was investigated by measuring specific oxygen uptake rate (Q$_{O2}$) used as an indicator representing the respiratory capacity of S. cerevisiae in batch and continuous cultures. The respiratory capacity of aerobic glucose metabolism in S. cerevisiae was also monitored after glucose pulse-addition in a continuous culture (D=0.2, 1/hr), in which glucose was utilized through respiratory metabolism. The deficiency of myo-inositol was found to lead to both the decrease of the maximum specific oxygen uptake rate (Q$_{O2max}$) observed from the batch as well as in the continuous culture experiment and the decrease of the respiratory capacity of aerobic glucose metabolism of S. cerevisiae determined from the glucose pulse-addition experiment, in which the glucose flux into respiratory and fermen- tative metabolism was quantitatively analyzed.

• Journal of Microbiology
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• 제33권4호
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• pp.315-321
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• 1995

The relationship between morphological differentiation and production of trypsin-like protease (TLP_ in streptomycetes was studied. All the Streptomyces spp.In this study produced TLP just before the onset of aerial mycelium formation. Addition of TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP activity. Addition of 2% glucose to the Bennett agar medium repressed both the aerial mycelium formation and TLP production in S. abuvaviensis, S. coelicolor A3(2), S exfoliatus, S. microflavus, S. roseus, s. lavendulae, and S. rochei. However the addition of glucose did not affect S. limosus, S. felleus, S. griseus, S. phaechromogenes, and S. rimosus. The glucose repression on aerial mycelium formation and production of TLP was relieved by the addition of glucose anti-metabolite (methyl .alpha.-glucopyranoside). Therefore, it was concluded that TLP production is coordinately regulated with morphological differentiation and TLP activity is essential for morphological differentiation in streptomycetes. The proposed role of TLP is that TLP participates in the degradation of substrate mycelium protein for providing nutrient for aerial mycelial growth.

• Biomolecules & Therapeutics
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• 제12권4호
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• pp.228-234
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• 2004

Brazilin shows hypoglycemic effect in diabetic animals through enhancement of glucose metabolisms in insulin responsive tissues. One of the major mechanisms of brazilin to enhance glucose metabolism is stimulation of glucose transport in adipocytes. In this study, the essential molecular moiety of brazilin for the stimulation of glucose transport was investigated. We found that brazilin undergoes a structural change in physiological buffer and produces hydrogen peroxide. Methylation of hydroxyl group of brazilin or addition of catalase along with brazilin resulted in the complete inhibition of brazilin-induced glucose transport in adipocytes. Because hydrogen peroxide increases glucose transport by inhibition of phosphatases, we examined the effect of brazilin on phosphatase activity. Brazilin inhibited phosphatases in a wide range of activity, and protein phosphatase 1 and 2A were also inhibited. These results suggest that the production of hydrogen peroxide by oxidation of catechol hydroxyl group of brazilin mediates glucose transport through inhibition of phosphatases which otherwise decrease glucose transport in adipocytes.

• 한국식품영양과학회지
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• 제19권3호
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• pp.224-228
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• 1990

Cabbage contained high peroxidase activity among tested plant sources. The cabbage peroxi-dase can replace horseradish peroxidase to assay glucose with glucose oxidase. The amount of glucose can be determined quantitatively by glucose oxidase-cabbage peroxidase. The opti-mum pH and temperature for enzymatic glucose determination by glucose oxidase-cabbage peroxidase were 6.0 and 35-45$^{\circ}C$ respectively. The glucose assay was inhibited by addition of various metal salts such as mercuric chloride lead acetate silver nitrate ammonium molyb-date sodium tunstate and cupric sulfate. The relationship between absorbance and amount of glucose was linear up to 8.33 mM glucose in the assay mixture under the assay conditions.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.113-118
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• 2002

Alpha-lipoic acid is a known hypoglycemic agent that may be useful in the treatment of diabetes. The objective of this study was to investigate the fate of glucose in isolated muscles incubated with lipoic acid by determining its direct effects on specific metabolic and signaling pathways. Soleus muscles from healthy rats were incubated with lipoic acid in the absence or presence of insulin. Glucose transport, glycogen synthesis, glucose oxidation and lipid synthesis were determined and affects on major pathways associated with insulin signaling were evaluated. Glucose transport was not significantly altered by the addition of lipoic acid to the incubation medium. However, lipoic acid decreased glycogen synthesis in comparison to controls. Glucose oxidation was moderately increased while de-novo lipid synthesis from glucose was inhibited. Wortmannin repressed insulin stimulation of glucose incorporation into glycogen, an effect that was augmented by the combined treatment of wortmannin and lipoic acid. Basal and insulin-stimulated serine phosphorylation of Akt was not changed by the addition of lipoic acid to the incubation medium. These data show that in this in vitro model, lipoic acid did not significantly affect glucose uptake but dramatically modified pathways of glucose metabolism within muscle tissue.