• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.185-190
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• 1981

1. $\alpha$-amylase from B. circulans F-2 was purified with specific activity 55.0 u/mg. protein (about 23 times of the original specific activity) and the yield of 25.5%, by means of corn starch absorption, salting out with ammonium sulfate (80% saturation), gel filtration on Bio-Gel P-100 and DE-32 column chromatography. 2 The purified enzyme showed two closely migrated protin bands on polyacrylamide disc gel electrophoresis, both of which have amylase activity judging from the activity staining of the gel. On SDS-polyacrylamide disc gel electrophoresis, however, the purified enzyme showed a single band suggesting that those two bands are the charge isomers of an amlyase having the slightly different charge. 3. Plot of log mobility of two bands versus polyacrylamide gel concentration according to Hedrick and Smith gave the parallel lines indicating them to be charge isomers. 4. To confirm the action pattern of two enzyme protein bands, each band was separated and was eluted from the gel and eluates were incubated with soluble starch. Oligosaccharide pattern produced by each eluate was examined by paper chromatography. The eluates of two bands showed the same action pattern. 5. The maltohexaose was the only hydrolysis product of soluble starch in the early stage of hydrolysis.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.358-362
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• 1988

Aqueous two-phase fermentation system was tested for the overproduction of extracellular enzyme through $\alpha$-amylase fermentation by Bacillus amyloliquefaciens. By employing aqueous two-phase system $\alpha$-amylase activity showed 25% increase compared to the result using regular medium and no deactivation of the enzyme was observed. The presence of polyethylene glycol was observed to promote the enzyme production, while to inhibit the growth of the microorganism. It is recommended that polyethylene glycol be added during the log-growth phase and dextran be added after the enzyme activity reaches Its maximum for efficient $\alpha$-amylase fermentation and in situ recovery of the enzyme.

• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.374-382
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• 2013

The objective of this study was determined to evaluate ${\alpha}$-amylase, ${\alpha}$-glucosidase, pancreatic lipase inhibition in vitro and DPPH radical scavenging activity of the several Korean resources plants. The ${\alpha}$-amylase inhibitory activity of Salicornia herbacea, Erythronium japonicum (flower) and Phragmites communis (root) in water extract showed relatively high 62.8%, 66.5% and 69.3%, respectively. The ${\alpha}$-amylase inhibitory activity of Citrus junos (pericarp) and Cornus officinalis in methanol extract was found to have an effect with 32.8% in Citrus junos (pericarp) and 60.9% in Cornus officinalis. Corylopsis coreana in both water and methanol extract had the highest ${\alpha}$-glucosidase inhibitory activity of 81.7% and 89.5%, while the extract of Portulaca oleracea, Ficus carica and Citrus junos was not measured ${\alpha}$-glucosidase inhibitory activity at given experiment concentration. Depending on the extraction solvent and the plant species, it was observed that there was a significant difference in ${\alpha}$-glucosidase inhibitory activity. The pancreatic lipase inhibitory activity showed relatively higher in the methanol extract than water extract except pericarp of Citrus junos. The DPPH radical scavenging activity of selected plants was much difference between measured plant species, and showed that the increase was proportional to the concentration. These results suggested that selected plants had the potent biological activity on carbohydrate, lipid Inhibitory activity and antioxidant activity, therefore these plant resources could be a good materials to develop medicinal preparations, nutraceuticals or health functional foods for diabetes or obesity.

• Archives of Pharmacal Research
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• v.8 no.2
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• pp.67-75
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• 1985

To find emylase inhibitors produced by microorganisms from soil, a strain which had a strong inhibitory activity against bacteria .alpha.-amylase was isolated from the soil smaple collected in Seoul. The morphological and physiological characteristics of this strain on several media and its utilization of carbon sources showed that it was one of Streptomyces specties according to the international Streptomyces Project method. The amylase inhibitor of this strain was purified by means of acetone precipitation, adsorption on Amberlite XAD-2, and column chromatography on Amberlite CG-50 and SP-Sephadex C-25. The inhibitor was stable at the pH range of 1-10 and at 100.deg.C for half an hour, and had inhibitory activities against other amylases such as salivary .alpha.-amylase, pancreatic .alpha.-amylase, fungal .alpha.-amylase and glucoamylase. The kinetic studies of the inhibitor showed that its inhibitory effect on starch hydrolysis by .alpha.-amylase was non-competitive.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.42-47
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• 2008

Prevention of postprandial hyperglycemia is important, as it is implicated in the development of macro- and microvascular complications associated with diabetes. An inhibitor of ${\alpha}$-amylase which acts in the first step of carbohydrate digestion, is expected to be a suppressor of postprandial hyperglycemia. This study investigated the porcine pancreatic ${\alpha}$-amylase inhibitory activity of the extracts from buckwheat (Fagopyrum esculentum) flower, leaf, stem and grain. Flower, leaf, stem and grain of buckwheat were extracted by water and ethanol (40%, 70%, 100%), respectively. Flower and leaf extracts were more effective ${\alpha}$-amylase inhibitors than stem and grain extracts in all tested solutions. Ethanol extracts were more effective than water extracts or powders on the ${\alpha}$-amylase inhibitory activities. At concentrations of $0.5%{\sim}10%$ (w/w, starch basis), the flower extracts of 40%, 70% and 100% ethanol lowered the enzyme activity by about 90% and the results were similar to the values of acarbose. At the same concentrations, the leaf extracts of 100% ethanol lowered the enzyme activity by about 90%. These results suggest that buckwheat flower and leaf ethanol extracts may delay carbohydrate digestion and lower postprandial hyperglycemia.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.158-161
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• 1998

The study was carried out to examine changes of ${\alpha}$-amylase activity and free proline contents during rice germination under low temperature($13^{\circ}C$). The plant height, root length, and germination rate were investigated during seed germination under the low temperature. Those growth chracteristics were the highest in Dongjin cultiver compared with other rice cultivars. The ${\alpha}$-amylase activity of the 9 days after germination was higher in Dongjin than those of Sangju and Koshihikari cultivars. The content of free proline was increased in all rice cultivars, when the germination of rice seeds was prolonged. As a result, it was concluded that ${\alpha}$-amylase activity and free proline content of Donjin cultivar were relatively increased higher under low temperature stress than those of other rice cultivars.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.56-60
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• 1998

Radish and Chinese cabbage were cultivated under hydrophonic culture to investigate the effect of chromium on germination, cell elongation, ${\alpha}$-amlyase activity, contents of chlorophyll and protein. With increasing concentration of cromium, germination, cell elongation, ${\alpha}$-amlyase activity were decreased in both radish and Chinese cabbage, the rate was higher in radish than in Chinese cabbage. Contents of chlorophyll a and b were also decreased and chlorophyll a was higher than chlorophyll b. As the concentration of chromium was increased inhibited in the order of protein> ${\alpha}$-amylase activity>chlorophyll a>chlorophyll b.

• Korean Journal of Medicinal Crop Science
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• v.17 no.5
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.831-838
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• 1996

This study was undertaken in order to elucidate the effects of raw, roast and steamed buckwheat on fecal protein, Pancreas weight, the activities of $\alpha-amylase,$ chymotrypsin and lipase 91 the pancreas, and $\alpha-amylase,$ chymotrypsin and trypsin activities of the feces in streptozotocin-induced diabetic rats. Fecal proteins of raw, roast and steamed buckwheat diabetic groups were increased up to 99%, 91%, 103%, respectively compared to those of the diabetic control group. Feeding of buckwheat diet increased pancreas weight, especially raw buckwheat diabetic group(p<0.05). Pancreatic chymo-trypsin activity was decreased in buckwheat diabetic groups compared to diabetic control group, wheres any significant difference was observed in $\alpha-amylase$ and lipase activities. Fecal chymotrypsin activi-ty was significantly increased in all buckwheat diabetic groups. Fecal trypsin activity was increased in roast buckwheat diabetic groups compared to diabetic control group and fecal $\alpha-amylase$ activity in buckwheat diabetic group was not significantly different. These results suggest that feeding of buckwheat diet enhances the impaired exocrine pancreatic function of diabetic rat.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.296-302
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• 2012

A bacterial strain was isolated from soybean paste fermented in a Korean Buddhist temple as a producer of the extracellular thermostable ${\alpha}$-amylase. The isolate YB-1234 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties. A gene encoding the thermostable ${\alpha}$-amylase of B. licheniformis YB-1234 was cloned into Escherichia coli and its nucleotide sequence was determined. The deduced amino acid sequence of ${\alpha}$-amylase was very highly homologous to those of the thermostable ${\alpha}$-amylases of B. licheniformis belonging to the glycosyl hydrolase family 13. The ${\alpha}$-amylase produced by recombinant E. coli carrying the ${\alpha}$-amylase gene exhibited maximal activity at pH 6.0, identical to ${\alpha}$-amylase in the culture filtrate of B. licheniformis, while the temperature profile was somewhat different between the two. Particularly, ${\alpha}$-amylase produced from B. lcheniformis is much more thermostable than that from recombinant E. coli. The predominant products resulting from the ${\alpha}$-amylase hydrolysis were glucose, maltose and maltotriose for maltotetraose and maltohexaose.