• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1260-1265
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• 2007

Magnetically separable enzyme-coated nanofibers were developed for the hydrolysis of starch. Stability of ${\alpha}-amylase-coated$ nanofiber was greatly improved and its residual activity was maintained over 92.7% after 32 days incubation at room temperature and under shaking conditions (200 rpm). The recovery of enzyme was high and enzyme activity after 10 recycle was 95.2% of its original activity. Developed enzyme-coated nanofibers were used for the hydrolysis of starch. When 0.5 mg of magnetically separable enzyme nanofibers was used, 40 g/l of starch (2 ml) was completely degraded within 40 min. The continuous enzyme reactor was developed and used for starch hydrolysis and 76% of starch (30 g/l) was hydrolyzed with 1 hr residence time.

• Journal of Environmental Science International
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• v.14 no.3
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• pp.359-366
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• 2005

Starch was crosslinked with epichlorohydrin. Crosslinked starch-filled waterborne acrylate (CSWAC) films were prepared by blending this crosslinked starch with waterborne acrylate. The thermal and mechanical properties of these films were investigated by thermogravimetric analysis (TGA), tensile strength and elongation test. The biodegradability was also studied by determination of reduced sugar products after enzymatic hydrolysis and the surface morphology was investigated by scanning electron microscopy (SEM). The CSW AC film showed significantly higher tensile strength and elongation than those of starch-filled waterbonre acrylate (SWAC). The biodegradability of this film was higher than that of native starch-filled acrylate film, and was increased by the addition of crosslinked starch to the acrylate film.

• Journal of Animal Science and Technology
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• v.62 no.6
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• pp.956-958
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• 2020

Lactobacillus plantarum SK156 was isolated from traditional Korean food. The genome of SK156 strain consists of a circular chromosome (3,231,383 bp) with guanine (G) + cytosine (C) content of 44.56%. Among the predicted 2,991 protein-coding genes, the genome included genes encoding for α-amylase, which hydrolyzes α-bonds of polysaccharides. Genomic sequencing of L. plantarum SK156 will give information on the mechanism involved in the enzymatic degradation of polysaccharides and its application for improving feed efficiency.

• Journal of Life Science
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• v.18 no.7
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• pp.1005-1010
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• 2008

In this study, we investigated the inhibitory effect of four solvent fractions of Alnus firma on ${\alpha}-amylase$, ${\alpha}-glucosidase$ and aldose reductase activities. The inhibitory test showed that methanol (MeOH) extract and hexane (HX) fraction strongly inhibited pork pancreatin and salivary ${\alpha}-amylase$ activity. The MeOH extract and HX fraction of Alnus firma at the concentration of 4 mg/ml inhibited more than 70% of pancreatin and salivary ${\alpha}-amylase$ activity. The inhibitory effect of fractions has different specificities against ${\alpha}-amylase$ from pancreatin and salivary. In addition, the MeOH extract and butanol (BuOH) fraction showed the highest inhibitory activity on yeast ${\alpha}-glucosidase$ at values of $IC_{50}$ $137.36\;{\mu}g/ml$ and $115.14\;{\mu}g/ml$ respectively. The MeOH extract and BuOH fraction showed the highest inhibitory activity on yeast ${\alpha}-glucosidase$ than commercial agent such as 1-deoxynorjirimycin and acarbose. Inhibition kinetics of solvent fractions showed that ${\alpha}-glucosidase$ has been inhibited noncompetitively by the MeOH, EA and BuOH fraction. The aldose reductase from human muscle cell had been inhibited strongly by the MeOH extract and EA fraction at 57.996% and 83.293% at the concentration of $50\;{\mu}g/ml$, respectively. These findings may contribute to biological significance in that ${\alpha}-amylase$, ${\alpha}-glucosidase$ and aldose reductase inhibitory compounds could be used as a functional food and a drug for the symptomatic treatment of antidiabetic disease in the future.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2222-2226
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• 2011

Amylase is a digestive enzyme that catalyses the starch into sugar. It has been reported that the green tea flavonoid (or polyphenols) (-)-epigallocatechin 3-gallate (EGCG) inhibits human salivary ${\alpha}$-amylase (HSA) and induced anti-nutritional effects. In this study, we performed docking study for seven EGCG-like flavonoids and HSA to understand the interaction mechanism of HSA and EGCG and suggest new possible flavonoid inhibitors of HSA. As a result, EGCG and (-)-epicatechin gallate (ECG) bind to HSA with complex hydrogen bonding interactions. These hydrogen bonding interactions are important for inhibitory activity of EGCG against HSA. We suggested that ECG can be a potent inhibitor of HSA. This study will be helpful to understand the mechanism of inhibition of HSA by EGCG and give insights to develop therapeutic strategies against diabetes.

• BMB Reports
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• v.37 no.6
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• pp.642-647
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• 2004

The lysine residues of Bacillus licheniformis $\alpha$-amylase (BLA) were chemically modified using citraconic anhydride or succinic anhydride. Modification caused fundamental changes in the enzymes specificity, as indicated by a dramatic increase in maltosidase and a reduction in amylase activity. These changes in substrate specificity were found to coincide with a change in the cleavage pattern of the substrates and with a conversion of the native endo- form of the enzyme to a modified exo- form. Progressive increases in the productions of $\rho$-nitrophenol or glucose, when para nitrophenyl-maltoheptaoside or soluble starch, respectively, was used as substrate, were observed upon modification. The described changes were affected by the size of incorporated modified reagent: citraconic anhydride was more effective than succinic anhydride. Reasons for the observed changes are discussed and reasons for the effectivenesses of chemical modifications for tailoring enzyme specificities are suggested.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.133-139
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• 2012

A bacterium, identified as $Bacillus$ $amyloliquefacies$, CNL-90 using 16S rDNA analysis, was isolated from malt grain. The optimal activities of its ${\alpha}$-amylase and protease were observed at pH 6 and $60^{\circ}C$, and at pH 6 and $50^{\circ}C$, respectively although their activities remained stable at pH 7 and $40^{\circ}C$for ${\alpha}$-amylase and at pH 7 and $50^{\circ}C$ for protease. After solid-state fermentation of $B.$ $amyloliquefacies$, CNL-90 on wheat bran for 72hr or 144hr, the ${\alpha}$-amylase and protease activities were 170,000 and 290,000 units/kg, and 290,000 and 310,000 units/kg, respectively. The viable bacterial cell counts were $1.5{\times}10^9$ CFU/g and $2.2{\times}10^9$ CFU/g at 72hr and 144hr of the solid-state fermentation, respectively. A feeding trial with a total of 127 piglets was also conducted. The animals were divided into two groups: an experimental group fed with the fermented product (63 piglets) and a control group (64 piglets). The growth rate of the experimental group was 6.66% higher than that of the control group (P<0.05). The results of this study indicate that the ${\alpha}$-amylase and protease from $B.$ $amyloliquefacies$, CNL-90 can be used for industrial applications due to their activity in production of carbohydrate hydrolysates.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.576-581
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• 1999

Effects of signal sequences, protein sizes and dissolved oxygen on the secretion of human lysozyme from a recombinant yeast were experimentally characterized. The systems consisted of Saccharomyces cerevisiae host SEY2102 that was transformed with two different plasmids. These plasmids were identical with an exception to the plasmid pMC614, which contained the native yeast MFα1 sequence and the plasmid pMC632 with the non-native rat α-amylase signal sequence. The expression of human lysozyme was controlled by the ADHI promoter. The native yeast MFαl signal sequence was more efficient than the non-native rat α-amylase signal sequence in directing the secretion of human lysozyme. Lysozyme secreted with the α-amylase signal was retained inside the cells and released to the medium very slowly, thereby causing a lower cell growth rate and a decreased product secretion rate. Lysozyme was secreted more efficiently than invertase, which is an order of magnitude bigger in molecular size compared to lysozyme, which was under the direction of the MFαl signal sequence, suggesting that protein sizes may affect the secretion efficiency. When expressed in anaerobic conditions in the medium where the ADHI promoter was derepressed, the amount of lysozyme secreted was about twice higher than that of the aerobic culture. However, the secretion rates were identical. This result showed that the dissolved oxygen level may affect the efficiency of protein secretion only, and not the secretion rate of the product protein.

• BMB Reports
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• v.40 no.4
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• pp.494-500
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• 2007

The endophytic bruchid pest Callosobruchus maculatus causes severe damage to storage cowpea seeds, leading to economical losses. For this reason the use of $\alpha$-amylase inhibitors to interfere with the pest digestion process has been an interesting alternative to control bruchids. With this aim, $\alpha$-amylase inhibitors from baru seeds (Dipteryx alata) were isolated by affinity chromatographic procedures, causing enhanced inhibition of C. maculatus and Anthonomus grandis $\alpha$-amylases. To attempt further purification, this fraction was applied onto a reversed-phase HPLC column, generating four peaks with remarkable inhibition toward C. maculatus $\alpha$-amylases. SDS-PAGE and MALDI-ToF analysis identified major proteins of approximately 5.0, 11.0, 20.0 and 55 kDa that showed $\alpha$-amylase inhibition. Results of in vivo bioassays using artificial seeds containing 1.0% (w/w) of baru crude extract revealed 40% cowpea weevil larvae mortality. These results provide evidence that several $\alpha$-amylase inhibitors classes, with biotechnological potential, can be isolated from a single plant species.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.149-156
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• 2014

Termites are wood pests that cause vast economic damage every year. They digest both cellulose and starch, but the enzymes for starch digestion have not been well characterized. We obtained complete amino acid sequence information on the KME1 ${\alpha}$-amylase from Reticulitermes speratus KMT1 through analysis of total mRNA sequences. The KME1 enzyme has two ${\alpha}$-amylase domains and is 68% identical to the ${\alpha}$-amylase from Blattellager manica, its closest relative in the GenBank database. Some unique features of its conserved region and its distant evolutionary relationship to other insect ${\alpha}$-amylases suggest that KME1 is a new type of ${\alpha}$-amylase.