• 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.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.479-485
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• 1986

A 5200 basepair DNA fragment containing the Bacillus amyloliquefaciens amyE gene, encoding liquefying $\alpha$-amylase (1,4-$\alpha$-1)-glucan glucanohydrolase, EC 3.2.1.1), has been inserted into BamHI site of the pUB110 and the hybrid plasmid was designated as pSKS3. The pSKS3 was transformed into the Bacillus subtilis KM2l3 as a host which is a saccharifying $\alpha$-amylase deficient mutant of Bacillus subtilis NA64, and the plasmid in the transformed cell was expressed $\alpha$-amylase production and kanamycin resistance. The $\alpha$-amylase production of the transformed cell was reduced to one fifth of that of the donor strain. The Bacillus subtilis KM2l3 tarring pSKS3 indicated that the amyE gene product is a polypeptide which has the same electrophoretic mobility with that of the Bacillus amyloliquefaciens, but different from the saccharifying $\alpha$-amylase of Bacillus subtilis NA64. It means that the amyE gene of pSKS3 originales from the Bacillus amyloliquefaciens.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.464-469
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• 1991

An $\alpha$-amylase producing bacterium, strain 2B, was isolated from soil and identified to genus Bacillus. To enhance $\alpha$-amylase productivity, strain 2B was mutagenized successively with nitrosoguanidine. For an efficient selection of a-amylase hyperproducers, mutants which produced $\alpha$-amylase in the presence of glucose were isolated. The resultant mutant HG4, which was classified as constitutive and catabolite derepressed hyperproducer of a-amylase, produced about 30 folds more $\alpha$-amylase than parental strain in medium containing lactose as carbon source. The strain HG4 grew rapidly and produced enzyme in parallel with cell growth. Moreover, its cell lysis did not occur until time of maximal yield of enzyme, which was considered to be a favorable characteristic for the production and purificiation of enzyme in industrial scale. The enzymatic properties of parental strain 2B and mutant strain HG4 were almost the same. The optimal temperature and pH for enzyme reaction was $70^{\circ}C$ and pH 6.0, respectively, in 'the presence of 0.6mM $Ca^[2+}$ as an effective stabilizer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.812-815
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• 2009

The effects of processing conditions on the ${\alpha}$-amylase activity of radish were investigated at various temperatures, pHs and drying conditions. The ${\alpha}$-amylase activity of radish root was 3.1-fold higher than that of radish trunk. As the freeze-dried radish was incubated at various temperatures and pHs, ${\alpha}$-amylase activity was stably maintained at pH range of $4{\sim}7$ and temperature of $25{\sim}40^{\circ}C$. When radish was processed to kakdugi and danmooji, the residual ${\alpha}$-amylase activity was 45.39% and 19.19%, respectively. Consequently, the ${\alpha}$-amylase activity was greatly affected by processing conditions such as heat treatment and pH. It is suggested that radish should be processed at below $60^{\circ}C$ and at neutral to acidic pH condition.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.271-275
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• 2004

Distylium racemosum Sieb. Et Zucc contains some compounds inhibit -amylase activity in experimental conditions. The inhibitory test showed that 50% acetone extracts from the bark and leaves of the plant strongly inhibited salivary -amylase activity. Proanthocyanidin(PA) which has strong inhibitory activity was extracted from the leaves by chromatography on Sephadex LH-20. The inhibitory activities and the inhibition kinetics of the PA were studied against three kinds of enzymes: human salivary ${\alpha}-Amylase$ (SAA), pork pancreatin ${\alpha}-Amylase$ (PAA) and yeast ${\alpha}-Glucosidase$ (AG). Then the activities of PA against SAA, PAA and AG were compared with those of acarbose, a commercial agent. The inhibitory activities of PA were stronger than those of acarbose. Inhibition kinetics of the PA showed competitive inhibition for SAA and PAA, and non competitive inhibition for GA.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.409-414
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• 2007

Effects of dimethipin on ${\alpha}$-amylase activity of barley seeds were investigated. In the treatments of $1{\mu}M\;and\;10{\mu}M$ dimethipin, the indexes of germination were reduced to 17% and 24 % respectively. After seed germination, dimethipin was added to germinated seedlings and then the seedlings were kept to measure seedling length under illumination for 7 days. In control, the length of seedling was 5.7 cm, but in the treatments of $1{\mu}M$ dimethipin and $10{\mu}M$ dimethipin, seedling lengths were 5.5 cm and 1.2 cm respectively. In the relationship between dimethipin concentrations and ${\alpha}$-amylase activities, there was a linear curve. The more dimethipin was added to the seeds, the more ${\alpha}$-amylase activities were inhibited. In the treatments of $1{\mu}M$ dimethipin and $10{\mu}M$ dimethipin, ${\alpha}$-amylase activities were reduced to 33% and 71% respectively. Dimethipin also inhibited ${\alpha}$-amylase activities increased by gibberellin and the content of soluble protein. Therefore, it could be suggested that dimethipin might inhibit directly the activities of hydrolysis enzymes including ${\alpha}$-amylase or the expression of ${\alpha}$-amylase genes as germination and seedling growth were severely disturbed.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.237-239
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• 1985

The effects of red light on the $\alpha$-amylase activity of barley during germination was studied. The $\alpha$-amylase activity was highest at 5th day on germination, showing rapid increase from the 3rd-day of germination. The highest activity of $\alpha$-amylase was shown among the groups treated by red light at 100 Lux luminous intensity for 3 hours a day. The $\alpha$-amylase activity of barley during germination under the red light increased to 44% compared with that of barley during germination under the dark. The protein content was not increased by red light.

• KSBB Journal
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• v.6 no.2
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• pp.143-146
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• 1991

The liquifying $\alpha-amylase$ production from B. subtilis, A. oryzae and B. natto using wheat and rice bran as low cost culture medium was investigated. Among 3 strains, B. natto showed heights productivity of $\alpha-amylase$ in the outer wheat bran medium. And the optimum culture condition is pH 6.8 and $37^{\circ}C$ for the production of $\alpha-amylase$. The $\alpha-amylase$ activity of the crude enzyme and the purified enzyme are 256 unit/ml and 10,700 unit/ml, respectivitly. The $\alpha-amylase$ from B. natto cultrtured in outer wheat bran medium was purified into nearly a pure state(98.7%). And the molecular weight of the purified $\alpha-amylase$ was 34,000.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.190-195
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• 1992

In the polyethylene glycol/dextran aqueous two-phase systems, volume ratio was increased and partition coefficient was decreased with the increase of potyethylene glycol molecular weight and concentration. However the volume ratio was decreased and the partition coefficient was increased with the increase of dextran molecular weight. On the other hand, the volume ratio and the partition coefficient were decreased with the increase of dextran concentration. Continuous enzymatic hydrolysis of soluble starch with $\alpha$-amylase which was produced by Bacillus amyloliquefaciens IF0 14141 was investigated in polyethylene glycol/dextran aqueous two-phase systems. Nonreacted soluble starch and $\alpha$-amylase were reused in these systems. $\alpha$-Amylase activity was maintained more than 100 hrs by recycling of $\alpha$-amylase from bottom of settler to reactor.

• KSBB Journal
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• v.9 no.4
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• pp.418-427
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• 1994

For the production of ${\alpha}$-amylase cloned from Bacillus licheniformis expressed in E. coli, cultivating factors including the concentrations of glucose, maltose and acetic acid were investigated. The results were as follows: 1) Maximum ${\alpha}$-amylase yield and maximum specific production rate obtained from glucose source were better than those achieved from maltose source. 2) The optimum production yield of ${\alpha}$-amylase was obtained at 1.0ml/$\ell$ or less of initial acetic acid concentration.