• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.446-452
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• 1997

Sugars in Korean Kochuzang, saccharified and fermented red pepper paste, were studied by HPLC, TLC and NMR. The sugars in Kochuzang were extracted by heating in boiling water bath for 3 min. Commercial Kochuzang was found to contain 0.8~6.5% of limit dextrin, 0.3~7.3% of maltotriose, 5.3~16.5% of maltose, 8.6~29.4% of glucose and 0.3~3.4% of fructose, but did not found sucrose. The sugars in domestic Kochuzang were found to contain 2.3~1.5% of limit dextrin, 3.3~6.9% of maltotriose, 6.1~11.5% of maltose, 6.1~11.7% of glucose and 3.4~5.2% of fructose and 3.6~3.8% of sucrose. Limit dextrin in Kochuzang of maker 1 and 3 showed both signal of $\alpha$-1, 4- and $\alpha$-1, 6-glucosidic linkage with its estimation ratio of 5:1 and 9.1:1, respectively, by 1H-NMR analysis.

• Applied Biological Chemistry
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• v.28 no.1
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• pp.1-7
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• 1985

Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was characterized with respect to substrate specificity, the reaction products and hydolysis rate on various carbohydrates. Maltopentaose, maltoheptaose, soluble starch, amylose, amylopectin, oyster glycogen and gelatinized starch of corn, potato, glutinous rice, green banana and arrow root were hydolyzed by this enzyme, but ${\alpha},{\beta},{\gamma}-cyclodextin$, sucrose, raffinose, lactose, pullulan, maltose, maltotriose and maltotetraose were not hydrolyzed. Among oligosaccharides, maltohexaose was favorably hydrolyzed by this enzyme and the main reaction product of oligosaccharides and polysaccharides was maltotetraose. Addition of pullulanase to this enzyme increased the hydolysis rate on gelatinized starches. tut it did not on raw starches. Among various starches, corn starch was favorably hydrolyzed by this enzyme, whereas it acted on potato starch, arrow root starch and high amylose corn starch weakly.

• 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.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.136-141
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• 1989

A raw starch-digesting enzyme from Streptomyces sp. 4M-2 was purified by ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. The specific activity of the purified enzyme was 51.22 RSU/mg protein and the yield was 4.5% of the total activity of the culture broth. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis and its molecular weight was estimated to be about 102, 000 daltons by SDS-polyacrylamide gel electrophoresis, The optimal temperature and pH for the enzyme activity were 42$^{\circ}C$ and PH 5.5, respectively. The enzyme had Km, value of 44.44mg/$m\ell$ for raw corn starch. The enzyme was activated by addition of calcium and barium ions. Corn amylose was degraded by the enzyme very easily and raw potato starch was also degraded easily. Main products of the enzymatic hydrolysis of raw corn starch were analyzed to be maltose and maltotriose. The enzyme was considered as $\alpha$-amylase.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.398-402
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• 1984

These experiments were conducted to investigate the substrate specificity, the hydrolysis products on the various carbohydrates and the hydrolysis rate on the various raw starches of the two purified glucoamylase produced by Rhizopus oryzae. Both of the glucoamylases hydrolyzed amylose, amylopectin, glycogen, soluble starch, pullulan, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose, but did not act on ${\alpha}-cyclodextrin$, ${\beta}-cyclodextrin$, raffinose, sucrose and lactose. When the reaction mixture of glucoamylase and polysaccharides were incubated $37^{\circ}C$for 32 hours, glucoamylase I hydrolyzed amylopectin, soluble starch and amyloses completely, but hydrolyzing glycogen up to only about 88%. Glucoamylase II hydrolyzed the previous four polysaccharides up to about 100%. Both of the glucoamylases produced only glucose for various substrates and did not have any ${\alpha}-glucosyl$ transferase activity. Both of the glucoamylases hydrolyzed raw glutinous rice starch almost complety, wheras they acted on raw potato starch, raw green banana starch, raw arrow root starch, raw corn starch, raw yam starch and raw high amylose corn starch weakly. Glucoamylase II hydrolyzed raw starches at the higher rate than glucoamylase I.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.248-254
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• 1986

The product specificity of Bacillus ${\alpha}-amylase$ on raw rice starch has teen studied by using HPLC and scanning electron microscopy (SEM). Analysis of starch degradation products digested by ${\alpha}-amylase$ showed considerable differences between raw and gelatinized rice. The hydrolysis of raw rice starch resulted in formation of more glucose and maltose than those of gelatinized starch. SEM revealed characteristic enzyme degradation patterns. Hollow curvatures were observed in gelatinized starch, indicating the substrate is hydrolyzed in the interior of the starch chain by Bacillus ${\alpha}-amylase$. In contrast, raw starch were hydrolyzed from the end of the substrate, resulting in pinholes over the surface of the starch granules.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.273-278
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• 1996

The research was undertaken to characterize the reaction mode of transglucosidase (TG) from Aspergillus niger for the production of isomaltooligosaccharides such as isomaltose, panose and isomaltotriose. TG hydrolyzed maltose to glucose units and produced panose and glucose by transglucosylation. TG hydrolyzed panose to maltose and glucose when panose was used as an initial substrate. The reaction patterns of products when isomaltose, isomaltotriose or isomaltotetraose were used as substrates were different from the case when maltose was used as a substrate. Maltotriose and maltose showed the same formation pattern of products. TG also produced isomaltooligosaccharides from maltooligosaccharides. The production of panote by TG from maltose was mathematically described by Michaelis-Menten kinetics. The kinetic constants, $V_{max}$ (the maximum velocity) and $K_m$ (Michaelis constant), were estimated by Lineweaver-Burk plot to be 400 M/min and 21.4 mM, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.470-475
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• 1997

This study was to determine the effects of rice varities on saccharification in producing sikhe using 45 different rice varities. Using Gancheok, Sinkeumo, Seoan and Gyehwa, sikhe showed the highest sweetness determined by refractometer, however sikhe using Sangiu, Namweon and Yeongdeog showed the lowest sweetness with difference of about 19%. Sugar composition of sikhe using Gancheok, rice variety, is fructose 3.6%, glucose 9.8%, maltose 78.3% and maltotriose 8.3%, analysed by High Performance Liquid Chromatography. Six-row malt showed better saccharification power than two-row malt. And 100 mesh sieved powder of malt was better in saccharification than 20 mesh sieved powder. Optimum saccharification temperature of six-row malt was $60^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.259-265
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• 1982

These experiments were conducted to investigate the hydrolysis products on the various oligosaccharides of Bacillus cirulans F-2 $\alpha$-amylase, and the hydrolysis rate on the various raw starches of Bacillus circulans F-2 $\alpha$-amylase, Bacillus amylotiquefaciens $\alpha$-amylase and Rhizopus niveus glucoamylase. The results obtained were as follows : 1. Maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose were hydrolyzed, but maltose and maltotriose were not hydrolyzed by Bacillus circulans F-2 $\alpha$-amylase. Among maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose, especially maltotetraose was hydrolyzed weakly by Bacillus circulans F-2 $\alpha$-amylase. 2. The Hydrolysis rate of oyster glycogen was slightly lower than soluble starch, amylose and amylopectin. 3. The hydrolysis rate of com starch was higher in shaking incubation than in stationary incubation, but the hydrolysis rate of potato starch was not definite according to kinds of enzyme. 4. On com, rice, arrowroot, high amylose corn, banana, sago, yam and potato starch, Bacillus circulans F-2 $\alpha$-amylase exhibited a remarkably higher hydrolysis rate than Bacillus amyloquefaciems $\alpha$-amylase and Rhizopus niveus glucoamylase.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.56-63
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• 2013

We have characterized the putative ${\alpha}$-glucosidase gene (st2525) selected by total genome analysis from the acidothermophilic crenarchaeon Sulfolobus tokodaii strain 7. The ORF was cloned and expressed as a fusion protein in Escherichia coli, and recombinant ST2525 was purified by Ni-NTA affinity chromatography. Maximum activity was observed at $95^{\circ}C$ and pH 4.0, and the enzyme exhibited stability with half-lives of 40.1 min and 7.75 min at extremely high temperatures of $100^{\circ}C$ and $105^{\circ}C$, respectively. The enzyme retained at least 85% of its maximal activity in the pH range of 4.0-11.0. ST2525 exclusively hydrolyzed ${\alpha}$-1,4-glycosidic linkages of oligosaccharides in an exo-type manner, with highest catalytic efficiency toward maltotriose. The enzyme also displayed transglycosylation activity, converting maltose to isomaltose, panose, maltotriose, isomaltotriose, etc. From these results, ST2525 could be potentially useful for starch hydrolysis as well as novel synthesis of oligosaccharides in industry.