• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.863-867
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• 2004

$\alpha$-Galactosidase from A. oryzae DR-5 was induced in the presence of melibiose, raffinose, galactose, and locust bean galactomannan. The enzyme was purified to homogeneity by precipitation with acetone followed by ion-exchange chromatography using DEAE-Sephacel. The purified enzyme showed a single band in both nondenaturing-PAGE and SDS-PAGE. The enzyme was a glycoprotein in nature by activity staining. The molecular weight of the purified enzyme was 93-95 kDa by SDS-PAGE. The enzyme exhibited the optimum pH and temperature at 4.7 and $60^\circ{C}$, respectively. $\alpha$-Galactosidase activity was strongly inhibited by $Ag^{2+}, Hg^{2+}, Cu^{2+}$, and galactose. EDTA, 1,10-phenanthraline, and PMSF did not inhibit the enzyme activity, whereas N-bromosuccinimide completely inhibited enzyme activity. Investigation by TLC showed complete hydrolysis of stachyose and raffinose in soymilk in 3 h at pH 5.0 and $50^\circ{C}$.

• Plant Biotechnology Reports
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• 제5권1호
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• pp.19-25
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• 2011

Tocopherols belong to the plant-derived poly phenolic compounds known for antioxidant functions in plants and animals. Activation of mitogen-activated protein kinases (MAPK) is a common reaction of plant cells in defense-related signal transduction pathways. We report a novel non-antioxidant function of ${\alpha}$-tocopherol in higher plants linking the physiological role of tocopherol with stress signalling pathways. Pre-incubation of a low concentration of $50{\mu}M$ ${\alpha}$-tocopherol negatively interferes with MAPK activation in elicitor-treated tobacco BY2 suspension culture cells and wounded tobacco leaves, whereas pre-incubated BY2 cells with ${\alpha}$-tocopherol phosphate did not show the inhibitory effect on stimuli-induced MAPK activation. The decreased MAPK activity was neither due to a direct inhibitory effect of ${\alpha}$-tocopherol nor due to the induction of an inhibitory or inactivating activity directly affecting MAPK activity. The data support that the target of ${\alpha}$-tocopherol negatively regulates an upstream component of the signaling pathways that leads to stress dependent MAPK activation.

• Journal of Microbiology and Biotechnology
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• 제2권3호
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• pp.166-173
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• 1992

The expression of Bacillus subtilis $\alpha$-amylase from the phoA-amyE fusion gene in recombinant E. coli was investigated under various environmental conditions. The overexpression of cloned $\alpha$-amylase caused retardations in cell growth and synthesis of alkaline phosphatase (AP) from the chromosomal phoA gene. The change of culture temperature from $37^\circ{C}$ to $30^\circ{C}$ increased the specific activities of both $\alpha$-amylase and $\beta$-lactamase by six and two times, respectively, whereas the AP activity remained unchanged. The experiments with chlorampenicol (a translation inhibitor) suggested the enhancement of $\alpha$-amylase activity at $30^\circ{C}$, and this was partly due to the stability of $\alpha$-amylase itself. The further decrease of the temperature to $25^\circ{C}$ slowed down both the cell growth and cloned-gene expression rate. The $\alpha$-amylase activity showed a maximum at pH of 7.4 while alkaline phosphatase was most effectively produced at pH of 8.3.

• 한국약용작물학회지
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• 제17권5호
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• pp.357-362
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• 2009

Compounds of isolated from roots extract of Pueraria thunbergiana were tested their inhibitory effects on $\alpha$-glucosidase and $\alpha$-amylase. Inhibitory activity of methylene chloride (MC) fraction and ethyl acetate (EA) fraction against $\alpha$-glucosidase showed more than 60% at a concentration of $500{\mu}g/m{\ell}$. Among the nine compounds tested on $\alpha$-glucosidase, biochanin A, (-)-tuberosin and calycosin from MC fraction and daidzein from EA fraction were stronger inhibitors than acarbose ($IC_{50}=530{\mu}g/m{\ell}$), and their $IC_{50}$ were 9, 144, 328 and $20{\mu}g/m{\ell}$, respectively. Biochanin A and (-)-tuberosin also inhibited $\alpha$-amylase activity as like as acarbose $IC_{50}=20.5{\mu}g/m{\ell}$), and their $IC_{50}$ were 22 and $348{\mu}g/m{\ell}$, respectively. Although daidzein was already known $\alpha$-glucosidase inhibitory effects, it was newly evaluated that biochanin A and (-)-tuberosin inhibited $\alpha$-glucosidase as well as $\alpha$-amylase, and that calycosin did $\alpha$-glucosidase.

• 한국식품영양과학회지
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• 제41권3호
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• pp.310-319
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• 2012

본 연구에서는 기능적 특성이 우수한 우유 단백질 소재를 개발하여 식품산업에 응용하고자 우유 ${\alpha}$-La의 영양생리학적 특성에 대하여 분석하였다. 우유 ${\alpha}$-La의 기능성을 향상 시키려는 시도로써 MTGase의 첨가가 이 단백질의 이화학적 및 면역학적 특성에 미치는 영향을 조사하고, 수종의 암세포주의 생육에 대한 억제 효과를 탐색하였으며, ${\alpha}$-La의 구조적 상태에 따라 항암활성의 관련성을 검토하였다. ${\alpha}$-La에 반응한 MTGase에 의해 생성된 중합체는 인체 내 가수분해효소에 의해 분해가 용이한 것으로 확인되었다. 위암 세포주에 ${\alpha}$-La을 10 mg/mL 농도로 처리한 경우 높은 세포독성을 나타냈다. ${\alpha}$-La과 올레산의 복합체인 BAMLET은 간암 세포주에서 ${\alpha}$-La에 비해 더 강한 활성을 보였다. BAMLET은 apo 상태로 상당량의 이차구조를 지니고 있지만, 소수성 중심부는 느슨하게 형성된 MG와 같은 형태를 지니고 있을 것으로 추정되었다. NMR 분석 결과, BAMLET은 1.2 ppm과 0.8 ppm에서 지방산 보조인자인 올레산과 상호 작용하는 것으로 분석되었다.

• 한국식품영양과학회지
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• 제37권4호
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• pp.405-409
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• 2008

민간요법에서 화농성 피부질환이나 염증성 질환에 대해 효과가 있다고 알려진 제비꽃(Viola mandshurica)의 항산화 활성과 항당뇨 활성을 조사하였다. 제비꽃 10 g에 200 mL의 네 가지 용매(메탄올, 에탄올, 아세톤, 물)를 각각 가하여 추출한 다음, 농축하여 각각의 용매별 추출물을 얻었다. 이용매별 추출물의 총 페놀 함량은 메탄올 추출물이 34.49 mg/g 갈산 당량으로 가장 높았고, DPPH 라디칼과 ABTS 라디칼 소거능은 아세톤 추출물이 $1,000{\mu}g/mL$ 농도에서 각각 21.13%와 43.53%로 가장 높은 값을 보였다. 환원력의 경우에는 물 추출물이 $1,000{\mu}g/mL$ 농도에서 0.454의 값으로 가장 높은 활성을 보였다. 항당뇨 활성은 ${\alpha}$-amylase와 ${\alpha}$-glucosidase에 대한 저해 활성으로 측정하였는데 아세톤 추출물이 가장 활성이 높았으며 $1,000{\mu}g$/mL 농도에서 모든 효소 활성들을 저해하였다. 이상의 결과로부터 제비꽃 추출물은 항산화능과, 당뇨 관련 효소에 대한 저해능이 있음을 확인할 수 있었다.

• Journal of Microbiology
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• 제42권3호
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• pp.223-227
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• 2004

An ${\alpha}$-glucosidase inhibitor, SKG-3, was isolated from the fruiting bodies of Ganoderma lucidum and its physico-chemical properties were characterized. It was a highly specific and effective reversible inhibitor of ${\alpha}$-glucosidase. It showed very potent inhibitory activity against a-glucosidase with an IC$\sub$50/ value of 4.6$\mu\textrm{g}$/$m\ell$, but no activity for any other glycosidases tested. Enzyme activity could be recovered upon dialysis, thus providing evidence for the reversibility of the inhibition. A Lineweaver-Burk plot indicated that the SKG-3 inhibition of ${\alpha}$-glucosidase was competitive.

• 한국대기환경학회지
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• 제20권4호
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• pp.515-521
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• 2004

The catalytic oxidation of volatile organic compounds (methanol. acetaldehyde) has been characterized using the copper phthalocyanine catalyst in a fixed bed flow reactor under atmospheric pressure. The catalytic activity for pretreatment conditions was examined by this reaction system. The catalytic activity was ordered as follows: metal free-PC＜Cu ($\alpha$)-PC＜Cu ($\beta$)-PC The formaldehyde, carbon monoxide as a partial oxidation product of methanol and acetaldehyde over Cu ($\alpha$)-PC catalyst were detected and the conversions of methanol and acetaldehyde were accomplished above 95% over Cu ($\alpha$) -PC, Cu ($\beta$) - PC catalyst at 35$0^{\circ}C$. The pretreated metal free -PC, Cu($\alpha$)-PC, Cu($\beta$)-PC catalysts have been characterised by TGA, EA and XRD analysis. The catalytic activity pretreated with air and $CH_3$OH mixture (P-4) or air only (P-5) was very excellent. XRD and EA results showed that Cu($\alpha$)-PC, Cu($\beta$)-PC were destroyed an(1 new metal oxide such as CuO were formed.

• 대한가정학회지
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• 제19권2호
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• pp.183-188
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• 1981

This study was conducted to investigate the effects of synthetic antioxidants con the degradation of angiotensin II which is made up of 8 amino acids: Asp-Arg-Val-Try-Ile-Gly-Pro-Phe, by the $\alpha$-chymotrypsin and trypsin. the results obtained were as follow; 1. Dibutyl hydroxytoluene, butyl hydroxyanisole and sodium L-ascorbate showed no inhibitory effect on the activity of $\alpha$-chymotrypsin on the angiotensin II, but ethyl protocathechuate inhibited. its activity at the concentration of 100ppm. However, the angiotension II was gradually degradated by $\alpha$-chymotrypsin after one hour incubation with ethylprotecathechuate. 2. Butyl hydroxyanisole inhibited trypsin activities above 100ppm, but no inhibitory activities was observed by the other antioxidants used in this experiment.

• 생명과학회지
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• 제11권4호
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• pp.371-378
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• 2001

The effects of the RM 60 series on DNA replication systems were examined by using simian virus 40 (SV40) DNA replication system in vitro. The RM 60 series inhibited the DNA replication in the initiation step rather than in the elongation step. Polymerase$\alpha$-primase activity and toposiomerase I activity study were performed subsequently, the RM 60 seies increased the polymerase $\alpha$-primase activity in a low dose, but decreased the activity in a higher dose. The topoisomerase I activity was inhibited by the RM 60 series. This result suggests that the RM 60 series might inhibit some molecules which are required to establish replication forks during the initiation step of the DNA replication.