• Journal of Ginseng Research
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• v.24 no.1
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• pp.41-45
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• 2000

Maltooligosaccharides were produced from ginseng starch by hydrolysis of $\alpha$-amylase. And it was investigated that physicochemical properties and intestinal bacteria growing effort of maltooligosaccharides. The optimum level of the ginseng maltooligosaccharides was produced when 10% ginseng starch was hydrolyzed with 50 unit of Amano A $\alpha$-amylase per gram starch at 85。C for 24h. Viscosity and water holding capacity of the ginseng maltooligosaccharides were 37.7 cps at 20。C and 110.1% at 75% relative humidity, respectively. The ginseng maltooligosaccharides enhanced the growth of Bifidobaterium infantis.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.447-452
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• 2014

To isolate novel and useful microbial enzymes from uncultured gastrointestinal microorganisms, a fecal microbial metagenomic library of the pygmy loris was constructed. The library was screened for amylolytic activity, and 8 of 50,000 recombinant clones showed amylolytic activity. Subcloning and sequence analysis of a positive clone led to the identification a novel gene (amyPL) coding for ${\alpha}$-amylase. AmyPL was expressed in Escherichia coli BL21 (DE3) and the purified AmyPL was enzymatically characterized. This study is the first to report the molecular and biochemical characterization of a novel ${\alpha}$-amylase from a gastrointestinal metagenomic library.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1528-1534
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• 2009

This study was designed to evaluate the anti-obesity and hypoglycemic effects of Gugija (Lycium chinense Mill) extracts in 3T3-L1 adipocytes. We investigated the $\alpha$-amylase and $\alpha$-glucosidase inhibitory activities of extracts from Gugija. Gugija was extracted by 70% EtOH and 80% MeOH and aqueous, respectively. A single oral dose of Gugija extract inhibited the increase of blood glucose levels significantly at 0, 30, 60, 90 and 120 min and decreased incremental response areas under the glycemic response curve. These results suggest that Gugija 70% EtOH extracts may delay carbohydrate digestion and reduce postprandial hyperglycemia. In addition, triglyceride content in 3T3-L1 adipocytes decreased at higher concentrations of Gugija 70% EtOH extract. Free fatty acid content in 3T3-L1 adipocytes was increased at higher concentrations of Gugija 70% EtOH extract. Also, glucose transporter 4 (GLUT4), the key insulin signaling pathway transcription factor, was remarkably increased by the Gugija 70% EtOH extract when compared to those of control cells in protein expression levels. Therefore, Gugija can be developed as an effective anti-obesity and hypoglycemic agent.

• Journal of Life Science
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• v.11 no.2
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• pp.92-93
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• 2001

Bacillus sp. KYJ 963, which was isolated from Korean salt-fermented anchovy (anchovy-jeot), produces an extracellular ${\beta}$-amylase. The analysis of the digestion products of substrates by thin layer chromatography from the purified protein revealed that the enzyme could not hydrolyze maltose or ${\alpha}$-cyclodextrin. In the amino acid composition analysis, the major characteristic of the ${\beta}$-amylase was the high proportion of amino acids that possess short side chain such as glycine and alanine.

• KSBB Journal
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• v.14 no.6
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• pp.713-717
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• 1999

We have isolated a dextranase and amylase constitutive and hyper-producing mutant, Lipomyces starkeyi JLC26, from Lipomyces starkeyi ATCC74054 after mutation using UV irradiation. After partial purification of dextranase and amylase (together DXAMase;both activities were always co-purified) by ammonium sulfate precipitation, CM-Sepharose column chromatography, the specific activities of amylase and dextranase were 5367 and 3045 unit/mg, respectively. The pH effects for activity and stabiligy of both enzymes were similar to each other: Optimum pH and temperature for activity sere at 5.5 and 37$^{\circ}C$ and optimum ranges for stability were at pH 2.5-5.5 and 4-55$^{\circ}C$, respectively. The reaction end products of dextranase and amylase activities were found to the typical for those of endo-dextranase and endo-amylase. When the carbohydrase and maltotriose were reacted, glucose, maltose, isomaltose, maltotriose, panose and ${\alpha}(1{\rightarrow}6)$glucosylmaltotriose were produced by disproportionation reaction.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1586-1592
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• 2017

Some promoters were isolated and characterized from the genome of Leuconostoc mesenteroides SY2, an isolate from kimchi, a Korean traditional fermented vegetable. Chromosomal DNA of L. mesenteroides SY2 was digested with Sau3AI and ligated with BamHI-cut pBV5030, a promoter screening vector containing a promoterless cat-86. Among E. coli transformants (TFs) resistant against Cm (chloramphenicol), 17 were able to grow in the presence of $1,000{\mu}g/ml$ Cm and their inserts were sequenced. Transcription start sites were examined for three putative promoters (P04C, P25C, and P33C) by primer extension. Four putative promoters were inserted upstream of a promoterless ${\alpha}$-amylase reporter gene in $pJY15{\alpha}$. ${\alpha}$-Amylase activities of E. coli TFs containing $pJY15{\alpha}$ (control, no promoter), $pJY03{\alpha}$ ($pJY15{\alpha}$ with P03C), $pJY04{\alpha}$ (with P04C), $pJY25{\alpha}$ (with P25C), and $pJY33{\alpha}$ (with P33C) were 66.9, 78.7, 122.1, 70.8, and 99.3 U, respectively. Cells harboring $pJY04{\alpha}$ showed 1.8 times higher activity than the control. Some promoters characterized in this study might be useful for construction of food-grade expression vectors for Leuconostoc sp. and related lactic acid bacteria.

• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.431-436
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• 1986

The action of crude amylolytic enzymes extracted from Wonki and Chunmi sweet potatoes, ${\alpha}-amylase$, and ${\beta}-amylase$ on the sweet potato starches from Wonki (dry type) and Chunmi (moist type) were studied. The activity of crude amylolytic enzyme extracted from Wonki was higher than that extracted from Chunmi. The content of reducing sugar released from the reaction between crude amylolytic enzyme and Chunmi starch preheated at $70^{\circ}C$ was higher, but that preheated at $95^{\circ}C$ was lower than that from Wonki starch preheated at the same temperature. The activites of ${\alpha}-amylase$ and ${\beta}-amylase$ on the Wonki starch were higher than those of the Chunmi starch at the same conditions. Iodine affinity of amylolytic enzyme-treated starch was decreased and enzyme treated starch granule shape was found with porous structure having inner layers. X-ray diffraction patterns of amylolytic enzyme-treated starches were the Ca type like the intact starches and relative crystallinity was decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.791-795
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• 2011

This study examined the inhibitory activity of Ecklonia cava (EC) against ${\alpha}$-amylase to evaluate the availability of EC extract as a functional food agent. To verify the inhibitory activity of EC against porcine pancreatic ${\alpha}$-amylase, potato starch was used as a substrate. This analysis revealed that EC ethanol extract exhibited high ${\alpha}$-amylase inhibitory activity. For potential application within the food industry, the stability of the activity of EC ethanol extract under various heat and pH conditions was examined. The ${\alpha}$-amylase inhibitory activity of EC ethanol extract was not affected by the heat and pH treatment conditions used in this study. These results suggest that EC has the potential for development as a functional food agent.

• Preventive Nutrition and Food Science
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• v.17 no.1
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• pp.8-13
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• 2012

This study was designed to investigate whether Sargassum ringgoldianum extract may inhibit ${\alpha}$-glucosidase and ${\alpha}$-amylase activities, and alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice. The $IC_{50}$ values of Sargassum ringgoldianum extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.12 mg/mL and 0.18 mg/mL, respectively, which evidenced higher activities than those of acarbose. The blood glucose levels of the Sargassum ringgoldianum extract administered group were significantly lower compared to the control group in the streptozotocin-induced diabetic mice. Moreover, the area under the two-hour blood glucose response curve was significantly reduced and the absorption of dietary carbohydrates was delayed after administration of Sargassum ringgoldianum extract in the diabetic mice. Therefore, these results indicated that Sargassum ringgoldianum extract may help decrease the postprandial blood glucose level via inhibiting ${\alpha}$-glucosidase.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.153-163
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• 1988

This experiment was carried out to obtain the thermophilic fungus producing amylase and to investigate properties of the amylase. The selected strain, L-11 was obtained from soil in the vicinity of a hot spring and identified as Mocor sp.. And then the conditions for enzyme production in wheat bran cultures and properties of the crude enzyme were investigated. Furthermore, the enzyme was purified and the characteristics of purified enzyme were studied. The results obtained were as follows: 1. On the wheat bran medium added 80-100% water, amylase was effectively produced by the selected strain, L-11 for 48 hrs incubation at $50^{\circ}C$. 2. When the crude enzyme solution of the strain L-11 was passed through DEAE-Sephadex A-50 column chromatography, two peaks having amylase activity were obtained, and one peak was that of the main enzyme (enzyme of B peak). 3. The purified enzyme (enzyme of B peak) was recognized as single protein band on polyacrylamide disc gel electrophoresis. 4. In the hydrolysis reaction of soluble starch by the enzyme of main amylase, oligosaccharides produced at early stage were maltose and maltotriose mainly and procedure of the reaction maltose amount of maltose and glucose was increased. 5. The strain L-11 was recognized as a special strain producing ${\alpha}-amylase$ mainly and scarcely glucoamylase. 6. The optimum pH, optimum temperature, pH stability, and temperature stability of ${\alpha}-amylase$ were pH 4.0, $60-65^{\circ}C$, pH 4.0-9.0, and below$70^{\circ}C$.