• Journal of Life Science
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• v.7 no.1
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• pp.30-38
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• 1997

For screening thermostable $\alpha$-amylase from thermophiles, various samples from extreme environments such as hot spring and sewage near them, and compoat, wereexamined microbial growth in enrichment culture medium at 55$\circ$C on the assumption that enzymes from thermophiles are inevitable thermostable. One strain showing higher $\alpha$-amylase activity was pure cultured and designated as Bacillus sp. TR-25 from the results of morphological, cultural and physiological characteristics. The most important carbon sourses for the enzyme production were soluble starch, dextrin, potato starch and corn starch. Glucose and fructose had a catabolite repression on the enzyme production. The good nitrogen sources for the enzyme production were yeat extract, nutrient broth, tryptone, corn steep liquor and ammonium sulfate. The enzyme production was accelerated by addition of CaCl$_{2}$. $\cdot $ H$_{2}$O. The optimal medium composition for the enzyme production was soluble starch 2.0%, yeast extract 0.55, CaCl$_{2}$ $\cdot $ 2H$_{2}$O 0.015, Tween 80 0.001%, pH8.0, respectively. In jar fermenter culture, this strain shows a rapid growth and required cheaper carbon and nitrogen source. These properties are very useful to fermentation industry. The $\alpha$-amylase of this strain demonstrated a maximum activity at 80$\circ$C, pH 5.0, respectively. And calcium ion did not improve thermostability of the enzyme. At 10$0^{\circ}C$, this enzyme has 235 of relative activity. Transformation was carried out by thermophilic Bacillus sp. TR-25 genomic DNA. As a result, the transformant has increased thermostable $\alpha$-amylase activity.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.265-272
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• 1988

This experiment was carried to investigate the germination pattern in relation to temperatures and lights, and the emergence pattern in relation to seeding depths, lights and the alpha amylase activity of Youngia sonchifolia, Lactuca indica var. laciniata, Ixeris dentata var. albiflora and Ixeris polycephala. In Y. sonchifolia, the optimum germination temperature was $25^{\circ}C$, the optimum seeding depth to emerge was 0 mm and it could emerge in 0-5mm. In L. indica var. laciniata under cool storage, the optimum germination temperatures were $19^{\circ}C-28^{\circ}C$, the optimum seeding depth was 5mm and it could emerge in 0-20mm. In L. indica var. laciniata under room storage, the optimum germination temperature was $25^{\circ}C$ the optimum seeding depth was 5mm and it could emerge in 0-10mm. In I. dentata emerge was and 0mm and it could emerge in 0-5mm. In I. polycephla, the optimum temperatures were $16^{\circ}C-19^{\circ}C$, the optimum seeding depth to emerge was 0mm and it could emerge in 0-5mm. The alpha amylase activity was lower Y. sonchifolia, L. indica var. laciniata and I. dentata var. abiflora than barley cultivar Dongbor#1. And the increased pattern of alpha amylase activity was likely to it of germination rate.

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.26-30
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• 1993

Strain of treptomyces minoensis DMCJ-144 was tried to be improved so that it produces much more the $\alpha$-amylase inhibitor. Streptomyces minoensis DMCJ-144 was treated with 1 mg/mι (pH 9.0) of N-methyl-N'-nitro-N-nitrosoguanidine at $30^{\circ}C$ for 60 min and irradiated with UV light distanced 30 cm for 20 min. After mutagenesis, surviving colonies were cultured on the CM contaning acriflavine ($10{\mu}g/ml$) three times in order to enhance the mutability. And then through multi-level screening, colonies that ${\alpha}$-amylase inhibitor productibility. was Improved were selected by modified-blue value method. After third acriflavine treatment, $\alpha$-amylase inhibitory activities of selected colonies were found to be much better as compared with that of parent strain. One mutant strain showed 5.4 time inhibitory activity than the parent strain.

• Food Science and Preservation
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• v.21 no.2
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• pp.254-263
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• 2014

This study was carried out to analyze the effects of water and 70% ethanol extract on the antioxidative and antidiabetic activities of Smilax china L., a vine shrub belonging to the lily family. The activities of the extracts were measured based on the total phenolic and flavonoid contents and through on the results of the antioxidant tests, such as the electron-donating ability, ABTs radical scavenging activities, SOD-like activity, xanthine oxidase inhibition effect, antioxidant protection factor (PF), TBARs content and ACE inhibition activity, and ${\alpha}$-glucosidase, and ${\alpha}$-amylase inhibition activity. The resulting total phenolic and flavonoid contents of the 70% ethanol extract from S. china L. were greater than those of the water extract from S. china L. With regard to the results of the antioxidant tests, such as the electron-donating ability, ABTs radical scavenging activity, SOD-like activity, xanthine oxidase inhibition effect, antioxidant protection factor (PF), and TBARs content, those from the 70% ethanol extract from S. china L. were greater than those from the water extract from S. china L. Also, with regard to the ACE inhibition effect and ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibition, those from the 70% ethanol extract from S. china L. were greater than those from the water extract from S. china L. All these findings show that the 70% ethanol extract from S. china L. has greater antioxidative and antidiabetic effects and can be used as a preventive agent for oxidation and diabetes.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.246-252
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• 2012

After a mixed carbohydrate diet, inhibition of ${\alpha}$-amylase and ${\alpha}$-glucosidase involved in the digestion and absorption of carbohydrates can significantly decrease the postprandial increase of blood glucose level. In the course of screening these useful enzyme inhibitors, we selected five kinds of bean, using an in-vitro enzyme inhibition assay method. To evaluate the effect of germination process on the functionality of the bean, we investigated the inhibitory activities of the water extracts of non-germinated bean and germinated bean against ${\alpha}$-amylase and ${\alpha}$-glucosidase, relevant to postprandial hyperglycemia. We also investigated the oxygen radical absorbance capacity(ORAC), total phenolics content, and postprandial blood glucose lowering effect in rats(Sprague-Dawley rat model). Most germinated beans showed significantly higher ${\alpha}$-glucosidase inhibitory activity, compared with non-germinated beans. Among germinated beans, Glycine max had the highest ${\alpha}$-glucosidase inhibitory activity(53.3%). The water extract of germinated Phaseolus vulgaris L. had the highest ${\alpha}$-amylase inhibitory activity(95.1%), followed by Glycine max(58.7%), and Glycine max L. Merr(54.1%). Furthermore, the five germinated beans also showed high antioxidant activities in ORAC assay. Results suggested that the germination process may improve and enhance the anti-hyperglycemia potential and antioxidant activity of the bean.

• Food Science and Preservation
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• v.23 no.1
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• pp.80-88
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• 2016

Seven kinds (acacia, cochineal, catechu, grape peel, persimmon, gallnut and clove) of color powders obtained from natural resources and their mixtures were evaluated for their biological activities, such as antioxidant (ABTS and DPPH radicals scavenging), cholesterol absorption, and COX-2 inhibitory activities. Catechu, gallnut and clove were selected for the further studies due to its the best activities. The cholesterol absorption, COX-2 inhibitory, ${\alpha}$-amylase inhibitory and ${\alpha}$-glucosidase inhibitory activities were measured using the mixtures of catechu, gallnut and clove. The ABTS radical scavenging activity of the seven types of natural color powders were higher than the DPPH radical scavenging activity. The cholesterol absorption activity was significantly higher in cloves. The COX-2 inhibitory activity was significantly lower in acacia. The ${\alpha}$-amylase inhibitory activity was higher in catechu and gallnut, indicating that there were no significant difference between two mixtures. The ${\alpha}$-glucosidase inhibitory activity was the highest in catechu, which was higher than that of the catechu-containing mixtures. From all these results, a synergistic effect could be obtained when utilizing a mixture of powders rather than using only individual type. Since the activity of each powder was different, further studies will be required for clarifying the interactions between mixtures.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.519-526
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• 2008

To improve the quality of traditional kochujang, strains with high protease and amylase activity were isolated and identified from Sunchang traditional kochujang. Twenty-three strains strongly producing protease and 16 strains strongly producing $\alpha$- and $\beta$-amylase were isolated by using 1% isolated soy protein agar medium and 2% starch agar medium, respectively. Protease activities of the IA7, I5, and IA2 strain were 22.5, 21.2, and 20.6 unit/mL, respectively, and were higher than those of the other strains. Stains with high $\alpha$-amylase activity included K9 (967.8 unit/mL), K14 (828.3 unit/mL), K13 (662.5 unit/mL), K8 (601.5 unit/mL), and K11 (405.9 unit/mL). The $\beta$-amylase activity of the K11 strain was the highest, 34.3 unit/mL, among the isolated strains. Based on morphological, physiological properties, and API 50CHB-kit test for assimilation of 49 carbohydrates, 8 strains selected according to protease, $\alpha$-amylase, and $\beta$-amylase activities were tentatively identified as Bacillus megaterium (IA2), Bacillus subtilis (IA7, 15), Bacillus amyloliquefaciens (K8, K9, K11, and K13), and Bacillus stearothermophillus (K14). The IA7, 15, and K11 strains were finally identified as B. subtilis (99% ID) based on 16S rDNA sequencing.

• Journal of Plant Biology
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• v.26 no.4
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• pp.173-180
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• 1983

L-canavanine was added to GAs treated barley seeds, and induced amylase activity, soluble protein content, and arginine content were mesured. Canavanine, added at the beginning of the incubation period, inhibited amylase activity and protein accumulation. Amylase activity decreased markedly by addition of canavanine at 6 hr after incubation, where soluble protein content was not affected. The addition of canavanine after 12 hr incubation did not show serioud inhibited effect on the amylase activity and protein accumulation. GAs incubation caused decrement in arginine content per mg protein, but it was somewhat recovered by canavanine treatment. The longer the time between GAs and canavanine addition was, the less the recovery ration was. Arginine content in the $\alpha$-amylase fraction (ammonium sulfate 20~50% saturation) was lower than in 0~20% fraction, but higher than in 50~80% fraction. These results and control expreiments, using cordycepin and cycloheximide, support the idea that canavanine might incorporate into protein.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.227-235
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• 2009

Many of the protective functions of saliva can be attributed to the biological, physical, structural, and rheological characteristics of salivary glycoproteins. Therefore, the development of ideal saliva substitutes requires understanding of the rheological as well as biological properties of human saliva. In the present study, we investigated the changes of salivary enzymatic activities by saliva substitutes and compared viscosity of saliva substitutes with human saliva. Five kinds of saliva substitutes such as Moi-Stir, Stoppers4, MouthKote, Saliva Orthana, and SNU were used. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined with an NbsSCN assay. $\alpha$-Amylase activity was determined using a chromogenic substrate, 2-chloro-p-nitrophenol linked with maltotriose. The pH values of saliva substitutes were measured and their viscosity values were measured with a cone-and-plate digital viscometer at six different shear rates. Various types of saliva substitutes affected the activities of salivary enzymes in different ways. Stoppers4 enhanced the enzymatic activities of hen egg-white lysozyme, bovine lactoperoxidase (bLP), and $\alpha$-amylase. Saliva Orthana and SNU inhibited bLP activity and enhanced $\alpha$-amylase activity. MouthKote inhibited $\alpha$-amylase activity. Moi-Stir inhibited the enzymatic activities of bLP and $\alpha$-amylase. The pH values were very different according to the types of saliva substitutes. Stoppers4, MouthKote, and Saliva Orthana showed lower values of viscosity at low shear rates and higher values of viscosity at high shear rates compared with unstimulated and stimulated whole saliva. Moi-Stir and SNU displayed much higher values of viscosity than those of natural whole saliva. Collectively, our results indicate that each saliva substitute has its own biological and rheological characteristics. Each saliva substitute affects the enzymatic activity of salivary enzyme and finally oral health in different ways.

• Proceedings of the Microbiological Society of Korea Conference
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• 1991.04a
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• pp.225-236
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• 1991

The genes encoding the thermostable $\alpha$-amylase and maltogenic amylase from Bacillus lichenciformis were cloned and expressed in E. coli. The recombinant plasmid pTA322 was found to contain a 3.1kb EcoRI genomic DNA fragment of the thermostable $\alpha$-amylase. The cloned $\alpha$-amylase was compared with the B. licheniformis native $\alpha$-amylase. Both $\alpha$-amylase have the same optimal temperature of $70^{\circ}C$ and are stable in the pH range of 6 and 9. The complete nucleotide sequences of the thermostable $\alpha$-amylase gene were determined. It was composed of one open reading rame of 1,536 bp. Start and stop codons are ATG and TAG. From the amino acid sequence deduced from the nucleotide sequence, the cloned thermostable $\alpha$-amylase is composed of 483 amino acid residues and its molecular weight is 55,200 daltons. The content of guanine and cytosine is $47.46mol\%$ and that of third base codon was $53_41mol\%$. The recombinant plasmid, pIJ322 encoding the maltogenic amylase contains a 3.5kb EcoRI-BamHI genomic DNA fragment. The optimal reaction temperature and pH of the maltogenci amylase were $50^{\circ}C$ and 7, respectively. The maltogenic amylase was capable of hydrolysing pullulan, starch and cyclodextrin to produce maltose from starch and panose from pullulan. The maltogenic amylase also showed the transferring activity. The maltogenic amylase gene is composed of one open reading frame of 1,734bp. Start and stop codons are ATG and ATG. At 2bp upstream from start codon, the nucleotide sequence AAAGGGGGAA seems to be the ribosome-binding site(RBS, Shine-Dalgarno sequence). A putative promoter(-35 and-10 regions) was found to be GTTAACA and TGATAAT. From deduced amino acid sequence from the nucleotide srquence, this enzyme was comosed of 578 amino acid residues and its molecular weight was 77,233 daltons. The content of guanine and cytosine was $48.1mol\%$. The new recombinant plasmid, pTMA322 constructed by inserting the thermostable $\alpha$-amylase gene in the EcoRI site of pIJ322 to produce both the thermostable $\alpha$-amylase and the maltogenic amylase were expressed in the E. coli. The two enzymes expressed from E. coli containing pTMA322 was reacted with the $15\%$ starch slurry at $40^{\circ}C$ for 24hours. The distribution of the branched oligosaccharides produced by the single-step process was of the ratio 50 : 50 between small oligosaccharide up DP3 and large oligosaccharide above DP3.