• Applied Biological Chemistry
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• v.39 no.6
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• pp.477-481
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• 1996

It has been shown that tannins have adverse effects on growth of animals and feed utilization. Tannins are usually classified into hydrolyzable and condensed types but the adverse effects are more marked in condensed tannin in hydrolyzable tannin. Furthermore, the principle condensed tannins found in banana fruits are pro types by the polymerization of flavan-3, 4-diols either alone or in combination with other flavonoids such as catechins. Tannin of the investigated banana(Banana; Musa sapientum LINN)fruits was fractionated into four or five molecular forms, according to the degree of polymerization by chromatography on a column of Sephadex LH-20. The protein-precitating capacity of the fraction noted tannins increased in degree polymerzation. The inhibitory effect of tannins on trypsin(EC 3. 4. 21. 4), ${\alpha}-amylase$(EC 3. 2. 1. 1) and lipase(EC 3. 1. 1. 3) activities in vitro also increased with the incraesed in degree of polymerization.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.898-904
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• 2014

The stability of Bacillus licheniformis alpha-amylase (BLA) under acid condition was enhanced through direct evolution using the error-prone polymerase chain reaction. One beneficial mutation site, H281I, was obtained in BLA. The specific activity of H281I was 161/352 U/mg, which was 62.6/27.5% higher than that of the wild-type (WT) (99/276 U/mg) at pH 4.5/6.5 and $95^{\circ}C$. The pH optimum for H281I was decreased about 1 unit, whereas no significant changes of optimum temperature and thermostability were observed compared with the wild type (WT). The $k_{cat}/K_m$ value of H281I was 1.7-/1.4-fold higher at pH 4.5/6.5, respectively, than that of WT. The structure model analysis indicated that the H281I mutation altered the predicted interaction between the amino acid residues at 281 and 273, thus creating a conducive local environment for substrate binding, as reflected by its decreased $K_m$, and consequently increased the specific activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.577-583
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• 2001

The digestive enzyme activities such as $\alpha-amylase$, trypsin and pepsin from the laboratory-reared river puffer Takifugu obscurus were measured from the time course of 1 day until the 65 day after hatching. In the case of $\alpha-amylase$, it was showed minimum activity of 0.0493 U/mg at the total length (TL) 10 mm, and showed maximum activity of 0.1480 U/mg at 19 mmTL. Trypsin and pepsin were showed their maximum activities of 0.0264, 0.0258 U/mg and 0.0178, 0.0201 U/mg when the total length of 16 and 24 mm, and represented remarkable correlations between the changes of enzyme activity and growth rate. The ontogenetic variations of digestive enzymes were represented clearly different patterns; i.e, the pepsin showed higher activity when the periods of larva ($4\~5\;mmTL$) and juvenile II ($19\~24\;mmTL$), however, the trypsin represented maximum activity at the stages of juvenile I ($11\~16\;mmTL$) and young fish (27 mmTL), respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.1102-1105
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• 2006

The effect of heat treatments on in vitro starch hydrolysis of proso millet, sorghum, Job's tears, and buckwheat by pancreatic ${\alpha}-amylase$ was investigated. Grain samples were tested raw, boiled in water, or steamed/roasted. Starch content of the grains varied from 59.5% in Job's tears to 65.5% in proso millet, and amylose content varied from 5.3% in Job's tears to 36.3% in buckwheat. The in vitro starch hydrolysis of raw and heat-treated grains continuously increased during 60 min of hydrolysis. The starch hydrolysis (%) of raw grains after 60 min incubation was in the order of buckwheat (5.7%), proso millet (33.0%), Job's tears (51.2%), and sorghum (57.6%). Grains treated with steaming/roasting appeared to have higher starch hydrolysis rates than those with boiling except proso millet. Hydrolysis rates of buckwheat with a high amylose content appeared to be lower, compared to proso millet, sorghum, and Job's tears containing low amylose contents.

• BMB Reports
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• v.37 no.4
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• pp.429-438
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• 2004

Complementary DNAs encoding $\alpha$-amylases (Amyl I, Amyl III) and glucoamylase (GA I) were cloned from Aspergillus awamori KT-11 and their nucleotide sequences were determined. The sequence of Amyl III that was a raw starch digesting $\alpha$-amylase was found to consist of a 1,902 bp open reading frame encoding 634 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. On the other hand, the sequence of Amyl I, which cannot act on raw starch, consisted of a 1,500 bp ORF encoding 499 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. The sequence of GA I consisted of a 1,920 bp ORF that encoded 639 amino acids. The signal peptide was composed of 24 amino acids. The amino acid sequence of Amyl III from the N-terminus to the amino acid number 499 showed 63.3% homology with Amyl I. However, the amino acid sequence from the amino acid number 501 to C-terminus, including the raw-starch-affinity site and the TS region rich in threonine and serine, showed 66.9% homology with GA I.

• KSBB Journal
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• v.15 no.1
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• pp.88-95
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• 2000

We have produced new-structured oligosaccharides using immoobilized mixed-enzyme reactor of destransucrase from Leuconostoc mesenteroides B-512FMCM and $\alpha$-amylase from Aspergillus oryzae. The reactors of immobilized mixed-exzyme beads were more efficient for the production of oligosaccharides than that of each immobilized enzyme bead in stirred-tank reactior(STR) or in packed-bed reactor(PCR). In continuous flow reactor, the immobilized mixed-enzyme bead in PBR was more stable than in STR, and 52% of initial yield was maintained for 200 hr. New structured-oligosaccharides (NOS) reduced the change of pH in the culture of Streptococcus mutans. It also showed an inhibitory effect on the growth of Staphylococcus aureus.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.34-39
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• 1996

We examined the effects of crude hemicellulose, alcohol-insoluble hemicellulose, high molecular weight soluble polysaccharide (HMS-P : MW>10 kDa) and low molecular weight souble polysaccharide (LMS-P : MW<10 kDa) fraction isolated from buckwheat (raw, roast and steam) on digestive enzyme activity in vitro. The enzyme activities were measured after the polysaccharides-enzyme mixtures were incubated at $37^{\circ}C$ for 5 min. Crude hemicellulose, alcohol-insoluble hemicellulose and residue lowered ${\alpha}-amylase$ activity, whereas HMS-P and LMS-P had no inhibitory effect. All polysaccharides except LMS-P lowered lipase activity. Crude hemicellulose, alcohol-insoluble hemicellulose, residue and HMS-P showed a marked decrease of trypsin and chymotrypsin activity but LMS-P showed a slight decrease of them.

• Journal of Animal Science and Technology
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• v.61 no.2
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• pp.98-108
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• 2019

Four Korean native steers ($511{\pm}17.2kg$; $2{\times}2$ replicated crossover design) fitted with duodenal cannulas were used to investigate the influence of oral administration of soluble whey protein (WP; 82.29% crude protein) on ruminal fermentation, gastrointestinal (GI) hormone secretion in the blood, pancreatic ${\alpha}$-amylase activity in the duodenum, and disappearance rate in each segment of the GI tract. Steers were orally fed the basal diet (control; TMR [total mixed ration] 9 kg/d) or the basal diet with enriched WP (400 g/d) for 14 days. The apparent crude protein disappearance rate in the rumen of the WP was higher than in control (p < 0.05). However, no difference between groups was observed in the apparent crude protein disappearance rate in the intestine and the apparent starch disappearance rates in the rumen, GI tract. The level of cholecystokinin, secretin, and ghrelin in serum and pancreatic ${\alpha}$-amylase activity in the duodenum of the WP also did not change. The changes in the level of blood urea nitrogen related to protein metabolism were higher in the WP than in the control (p < 0.05). However, the levels of total protein, lipid, carbohydrate and mineral metabolites did not change. Consequently, we suggest that the oral administration of WP in steers assisted in ruminal fermentation due to the population increase of microbes in the rumen but did not improve the starch digestion rate in the small intestine because GI hormone secretion in the blood and pancreatic ${\alpha}$-amylase activity did not change.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.125-131
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• 2019

We have isolated and identified 72 bacterial strains from four bentonite samples collected at the mining areas located in Gyeongsangbuk-do, Republic of Korea, and measured their hydrolytic enzyme (${\alpha}$-amylase, protease, and cellulase) activities to identify the isolates with industrial-use potential. Most of the isolates belonged to the Bacillaceae, with minor portions being from the Paenibacillaceae, Micrococcaceae, and Bacillales Family XII at the family level. Of the strains isolated, 33 had extracellular ${\alpha}$-amylase activity, 30 strains produced cellulase, and 35 strains produced protease. Strain MBLB1268, having the highest ${\alpha}$-amylase activity, was identified as Bacillus siamensis ($0.38{\pm}0.06U/ml$). Bacillus tequilensis MBLB1223, isolated from Byi33-b, showed the highest cellulase activity ($0.26{\pm} 0.04U/ml$), whereas Bacillus wiedmannii MBLB1197, isolated from Zdb130-b, exhibited the highest protease activity ($54.99{\pm}0.78U/ml$). These findings show that diverse bacteria of the Bacillaceae family adhere to and exist in bentonite and are potential sources of industrially useful hydrolytic enzymes.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.461-468
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• 2001

The effectiveness and safety of Enzyme Food, a group of dietary supplements designated by Korean Food Law, were evaluated and the possibility of HACCP (Hazard Analysis Critical Control Point) application was investigated. Chemical composition, enzyme activities and the degree of bacterial contamination in 12 samples of different brands sold in Korean market were measured. The chemical composition of the selected products varied and inconsistent to those claimed in the label description. It is known that effectiveness of Enzyme Food depends on enzyme activity, but enzyme activities of ${\alpha}-amylase$ varied from $1,793\;{\mu}g/min$ g to $159\;{\mu}g/min$ g and those of ${\beta}-amylase$ ranged from $171\;{\mu}g/min$ g to $11\;{\mu}g/min$ g. The protease activities varied from $27.57\;{\mu}g/min$ g to $0.18\;{\mu}g/min$ g. In coli-form bacterial test, positive reactions were appeared in the 50 % of the samples. Numbers of bacteria ranged from $1.3\;{\times}\;10^5\;to\;1.2\;{\times}\;10^9$. Five CCPs were identified; heating, inoculation, cultivation, drying and granulation. Consideration of HACCP system indicated that the pretreatment of raw material, checking of bacterial contamination and stability of enzyme activity during fermentation process were important factors for the quality of Enzyme Foods.