• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.592-599
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• 2012

Bacillus licheniformis ${\alpha}$-amylase (BLA), a thermophilic counterpart of Bacillus amyloliquefaciens ${\alpha}$-amylase (BAA), is an appropriate model for the design of stabilizing mutations in BAA. BLA has 10 more histidines than BAA. Considering this prominent difference, in the present study, three out of these positions (I34, Q67, and P407; located in the thermostability determinant 1 region and Ca-III binding site of BAA) were replaced with histidine in BAA, using the site-directed mutagenesis technique. The results showed that the thermostability of P407H and Q67H mutants had increased, but no significant changes were observed in their kinetic parameters compared to that of the wild type. I34H replacement resulted in complete loss of enzyme activity. Moreover, fluorescence and circular dichroism data indicated a more rigid structure for the P407H variant compared with that of the wild-type BAA. However, the flexibility of Q67H and I34H mutants increased in comparison with that of wild-type enzyme.

• BMB Reports
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• 제40권1호
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• pp.29-35
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• 2007

During the past decade, many salivary parameters have been used to characterize disease states. Ghrelin (GAH) is recently-discovered peptide hormone secreted mainly from the stomach but also produced in a number of other tissues including salivary glands. The aim of this work was to examine the relationship between active (aGAH) and inactive (dGAH) ghrelin in the saliva and other salivary parameters in type II diabetic patients and healthy controls. Salivary parameters were assessed in a single measurement of unstimulated whole saliva from 20 obese and 20 non-obese type II diabetes patients, and in 22 healthy controls. Total protein and alpha-amylase were determined by colorimetric methods, and glucose by the glucose-oxidase method. Saliva aGAH and dGAH levels were measured using a commercial radioimmunoassay (RIA) kit. Salivary concentrations of aGAH and dGAH ghrelin were more markedly decreased in obese diabetic subjects than in the two other groups. Glucose and alpha-amylase levels were higher in diabetic subjects than in controls. Furthermore, there were correlations between GAH levels and BMI, and between GAH and blood pressure. However, there was no marked variability in saliva flow rates among the groups. These results indicate that measurement of salivary GAH and its relationship to other salivary parameters might help to provide insight into the role of ghrelin in diabetes.

• Preventive Nutrition and Food Science
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• 제3권1호
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• pp.98-104
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• 1998

As an efffort ot construct LAB (latice acid bacteria), capable of utilizing starch as fermentation substrate without the aid of externally supplied enzymes, plasmid vectors containing the amyL($\alpha$-amylase/pullulansase gene) from Clostridium thermophydrosulfuricum, and glucoamylase cDNA from Asperigillus shirousamii were constructed and introduced itno E. coli and L. lactis. For expression in procaryotes , 1.9kb glucoamylase cDNA encoding the mature form of enzyme was PCR amplified and translationaly fused to a PCR amplified 260 bp fragment containing the promotor and secretion signals of amyl in the same reading frame. The production of $\alpha$-amylase, Apu, and glucoamlase in E. coli and L. lactis was confirmed by enzyme assay and zymography . Enzymeswere detected in both cellpellets and supernatants, indicating theworking of scretion signals in heterologous hosts. The efficiencies of secretion were varibale depending on the gene and host. The highest $\alpha$- amylase acitivity observed was 1.1 units and most activiity was detected from thecell pellets. The degree of gene expression in both hosts and the effect on the growth of hosts were examined.

• Preventive Nutrition and Food Science
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• 제6권4호
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• pp.206-210
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• 2001

Starch is an abundant resource in plant biomass, and it should be hydrolyzed enzymatically into fermentable sugars for ethanol fermentation. A genetic recombinant yeast, Saccharomyces cerevisiae GA-7458, was constructed by integrating the structural gene of both $\alpha$-amylase from Bacillus stearothermophilus and the gene (STA1) encoding glucoamylase from S. diastaticus into the chromosome of S. cerevisiae SH7458. The recombinant yeast showed active enzymatic activities of $\alpha$-amylase and glucoamylase. The productivity of ethanol fermentation from the pH-controlled batch culture (pH 5.5) was 2.6 times greater than that of the pH-uncontrolled batch culture. Moreover, in a fed-batch culture, more ethanol was produced (13.2 g/L), and the production yield was 0.38 with 2% of corn starch. Importantly, the integrated plasmids were fully maintained during ethanol fermentation.

• 한국식품영양과학회지
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• 제36권8호
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• pp.989-994
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• 2007

본 연구에서는 조릿대잎 추출물의 탄수화물 소화효소의 저해와 혈당강하효과를 조사하기 위해, 탄수화물 소화효소인 ${\alpha}-glucosidase$와 ${\alpha}-amylase$의 저해활성과 STZ 유발 당뇨생쥐를 이용한 혈당강하효과를 측정하였다. 조릿대잎 메탄올 추출물은 0.5 mg/mL 농도에서 yeast ${\alpha}-glucosidase$ 활성을 18.61% 저해하였으며, 메탄올 추출물의 ethylacetate층은 48.46%, buthanol층은 41.91%의 저해활성을 나타내어 40.31%의 저해활성을 보인 acarbose보다 ${\alpha}-glucosidase$ 저해효과가 높은 것으로 나타냈다. 또한 메탄올 추출물은 0.5 mg/mL 농도에서 ${\alpha}-amylase$ 활성을 22.16% 저해하였으며, ethylacetate층은 56.31%, buthanol층은 43.66%의 저해활성을 나타내어 41.14%를 나타낸 acarbose보다 높은 저해활성을 나타냈다. 따라서 조릿대잎 추출물 중 ethylacetate층과 buthanol층은 탄수화물 소화효소인 ${\alpha}-glucosidase$와 ${\alpha}-amylase$ 저해활성에서 제2형 당뇨병환자의 혈당 강하제로 처방되고 있는 acarbose보다 높은 저해능을 가진 것으로 나타났다. STZ으로 당뇨를 유발한 생쥐와 정상생쥐에게 시료의 수율 및 탄수화물 소화효소의 저해활성이 높은 buthanol층을 전분과 함께 경구 투여한 후 혈당 증가를 측정한 결과, 전분과 함께 조릿대 잎 추출물의 buthanol층을 경구 투여한 경우가 전분만 투여한 경우에 비해 투여 후 30, 60, 120분에 혈당 증가가 유의적으로 낮았으며(p<0.0l), 식후혈당증가 곡선의 면적에서도 대조군보다 유의적(p<0.0l) 으로 적음을 확인할 수 있었다. 이상의 연구 결과 조릿대잎 추출물중 ethylacetate층과 buthanol층은 acarbose보다 높은 ${\alpha}-glucosidase$, ${\alpha}-amylase$ 저해활성을 나타내었으며, 특히 buthanol층은 STZ 유발 당뇨생쥐를 통해 식후 혈당증가를 저하시키는 효과까지도 확인할 수 있었다.

• 한국식품영양과학회지
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• 제42권9호
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• pp.1439-1445
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• 2013

탄수화물분해효소 ${\beta}$-amylase(BA), ${\alpha}$-amylase(BAA), $cellulose+{\beta}$-glucanase(CBG)를 쌀과 함께 침지하여 쌀가루를 제조한 뒤 이 효소처리 쌀가루 100%를 이용하여 쌀쿠키를 제조해 쿠키의 품질 특성을 조사하였다. 효소처리 쌀쿠키 반죽의 밀도는 탄수화물 분해효소의 종류 및 효소처리의 유무에 따른 유의차를 나타내지 않았다. 효소처리 쌀쿠키의 퍼짐성은 비효소처리 쌀쿠키에 비해 크게 나타났으며 효소 ${\beta}$-amylase와 ${\alpha}$-amylase를 이용하여 제조한 쌀가루 쿠키를 제조했을 때 쿠키의 퍼짐성이 큰 것을 확인하였다. 효소처리 쌀쿠키 BA, BAA, CBG의 수분함량은 3.20~3.90%로 비효소처리 쌀쿠키 비해 유의적으로 낮은 수분함량을 나타내었다(P<0.05). 쌀쿠키의 색도 측정결과, 효소처리 쌀쿠키의 L값은 비효소처리 쌀쿠키에 비해 유의적으로 낮은 값을 나타냈으며, a와 b값은 효소처리 쌀쿠키가 비효소처리 쌀쿠키에 비해 유의적으로 낮은 값을 나타내었다(P<0.05). 쌀쿠키의 경도는 효소처리 쌀쿠키가 비효소처리 쌀쿠키에 비해 높은 경도를 나타내었으나 효소의 종류에 따른 차이를 나타내지 않았다. 관능적 특성으로 쌀쿠키의 특성강도 평가에서 쿠키의 고소한 향과 균열의 정도는 효소의 유무 및 효소의 종류에 따른 차이가 나타나지 않았다. 갈색의 정도와 쿠키의 고소한 맛의 강도는 비효소처리 쌀쿠키에 비해 효소처리 쌀쿠키에서 높게 나타났으며 효소 ${\alpha}$-amylase와 ${\alpha}$-amylase로 처리한 쌀가루로 제조한 쌀쿠키(BA)가 갈색의 정도와 쿠키의 고소한 맛이 적당한 강도를 나타내었다. 경도는 효소 처리 쌀쿠키의 강도가 유의적으로 높았으며 효소의 종류에 따른 유의적인 차이는 나타내지 않아 기계적 경도와 관능적인 측면의 경도가 유사한 결과를 나타내었다. 바삭함은 경도의 강도 평가와 유사한 경향을 나타내었다. 기호도 검사 결과에서, 비효소처리 쌀쿠키는 향, 외관, 맛, 조직감 및 전반적인 기호도에서 유의적으로 낮은 기호도를 나타내었다(P<0.05). 효소 ${\alpha}$-amylase를 이용한 쌀쿠키 BAA는 향, 맛 조직감에서 높은 점수를 받아 전반적인 기호도에서 높게 나타나 효소 ${\alpha}$-amylase를 0.1%의 농도로 처리하여 제조한 쌀가루로 쿠키를 제조할 때 일반 쌀쿠키에 비해 향, 맛, 조직감에서도 좋은 기호도를 나타내는 것으로 나타나 쿠키의 소재로 적합할 것으로 사료된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제1권2호
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• pp.123-129
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• 2000

Expression of the crylAcl gene of an acrystalliferous Bacillus thuringiensis strain under the control of the native or $\alpha$-amylase gene promoter was investigated. The crylAcl gene was cloned in a B. thuringiensis - E. coli shutle vector, pHT3101, undder the control of either the native promoter (pProAc) or the $\alpha$-amylase promoter from Bacillus subtilis (pAmyAc). These two recombinant plasmids were successfully expressed in B. thuringiensis subsp. kurstaki Cry B. The first transformant (ProAc/CB), harboring pProAc, expressed an about 130 kDa protein begining 24 hr after inoculations just as in the case of the wild type of B. thuringiensis subsp. kurstaki HD-73. The second pAmyAc-transformant (AmyAc/CB) began to express the gene just 6 hr after inoculation, but Western analysis showed that the activity of the $\alpha$-amylase promoter was relatively weaker than that of the native promoter. As expected, their toxicity against Plutella xylostella larvae was dependent on the amount of Cry1Acl protein expressed.

• Food Science and Biotechnology
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• 제17권2호
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• pp.302-307
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• 2008

Novel amylase inhibitors were synthesized via transglycosylation by Thermotoga maritima glucosidase (TMG). TMG hydrolyzes acarbose, acarviosine-glucose, and maltooligosaccharide by releasing $^{14}C$-labeled glucose from the reducing end of each molecule. When TMG was incubated with acarviosine-glucose (the donor) and glucose (the acceptor), two major transfer products, compounds 1 and 2, were formed via transglycosylation. The structures of the transfer products were determined using thin-layer chromatography (TLC), high-performance ion chromatography (HPIC), and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopy. The results indicate that acarviosine was transferred to glucose at either C-6, to give a $\alpha-(1{\rightarrow}6$) glycosidic linkage, or at C-3, to produce an $\alpha-(1{\rightarrow}3$) glycosidic linkage. The transfer products showed a mixed-type inhibition against porcine pancreatic $\alpha$-amylase; therefore, they may be useful not only as inhibitors but also as acarbose transition-state analogs to study the mechanism of amylase inhibition.

• 한국조리학회지
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• 제23권1호
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• pp.95-102
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• 2017

This study was activity of ${\alpha}-amylase$, glucoamylase of liquid Nuruk prepared using liquid Nuruk (NK) and Aspergillus kawachii (AK), Aspergillus niger (AN), Aspergillus oryzae (AO), Monascus kaoliang (MK). To investigate the relationship between the enzymatic activity and the total sugar content of liquid Nuruk depending on the types of Nuruk molds and the degree of rice-polishing. The activity of ${\alpha}-amylase$ depending on the types of Nuruk molds was shown to be 8.82, 8.72 units/mL in AN and AK treatments in brown rice liquid Nuruk at 24 hours after incubation, as the degree of rice-polishing increased, the activity of ${\alpha}-amylase$ was significantly lower (p<0.05). When brown rice was incubated in AN, it showed 8.83 units/mL at 48 hours after incubation, which was the highest activity, but there was no significantly difference (p<0.05), as the degree of rice- polishing was higher, the activity of ${\alpha}-amylase$ was lower. The activity of glucoamylase depending on the degree of rice-polishing showed 3,013 units/mL in AO treatment in brown rice liquid Nuruk at 24 hours after incubation, and the enzymatic activity was significantly higher (p<0.05). As the degree of rice-polishing increased, the activity of glucoamylase decreased, so liquid brown rice Nuruk showed the highest enzymatic activity, liquid white rice Nuruk was the lowest enzymatic activity. The highest enzymatic activity appeared in liquid Nuruk with brown rice at 48 hours after incubation. The activity of ${\alpha}-amylase$, glucoamylase showed higher enzymatic productivity as the degree of rice-polishing was lower, and there was an inverse correlation with the total sugar content.

• 한국식품과학회지
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• 제29권1호
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• pp.101-106
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• 1997

식혜원료로의 활용가능성 검토를 위해 현미와 벼를 $15^{\circ}C$에서 2일간 침지한 후 $15,\;20,\;25,\;30^{\circ}C$에서 최대 10일간 발아시키면서 잎눈의 성장, ${\alpha}-amylase$의 활력, 추출물의 함량, 당도 및 점도를 관찰하였다. 발아온도가 오를수록 현미와 벼의 발아속도, ${\alpha}-amylase$의 활성 증가 속도, 추출물의 함량 및 그 당도 증가 속도 모두 빨라졌으며, 추출물의 점도는 발아일수 경과에 따라 먼저 감소하다가 그 후 증가하는 경향을 보였다. 발아 현미와 벼의 ${\alpha}-amylase$의 활력은 발아 보리보다 작았으나 추출물의 함량 및 그 당도는 큰 차이가 없었다. 식혜제조시 발아 현미나 벼를 보리 엿기름 대신 사용할 가능성은 없으나 발아 현미를 백미 대신 식혜 원료로 사용할 경우 현미 자체를 원료로 사용한 경우보다 당화속도도 빠르고 당화 후 현미의 물성도 백미처럼 부드러울 수 있으리라 예상되었다.