• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.164-172
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• 2013

This study was carried out to investigate functional quality characteristics of extract obtained after sugar-leaching for 12 weeks (SLE) and extract obtained after lactic acid fermentation for 8 weeks (LFE) of mulberry leaves. The yield, sugar content, pH, and total acidity of SLE were 27%, 43 $^{\circ}Brix$, 4.6, and 0.45%. The yield, sugar content, pH, and total acidity of LFE were 166%, 33 $^{\circ}Brix$, 3.6, and 1.17% respectively. The lactic acid bacteria viable numbers ($1.2{\times}10^{10}$ CFU/ml) of LFE were more than those of SLE ($2.8{\times}10^2$ CFU/ml). The LFE expressed activities of hydrolytic enzymes (amylase, cellulase, pectinase, protease), but SLE did not express. The contents of acetic acid, citric acid, and malic acid of SLE were higher than those of LFE, but lactic acid content of LFE was higher than that of SLE. The main free sugars of SLE were glucose (200.93 mg/g), fructose (236.32 mg/g), and sucrose (18.41 mg/g), but LFE did not detect all free sugars. The contents of polyphenol, anthocyanin, and piperidine alkaloid of LFE were higher than those of SLE. ${\alpha}$-Glycosidase activities were inhibited 3.4% and 16.2% by SLE and LFE. These results suggest that lactic acid fermentation extraction is an effective method to increase the yield and contents of functional quality of mulberry leaves extract.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.225-238
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• 1989

These studies were conducted to investigate the extraction, purification and characterization of oriental pear (Niitaka. Pyrus pyrifolia Nak.) protease, and the results obtained were as follows: 1. Oriental pear protease was effectively extracted by the method of homogenizing pear pulp with 0.7 volume of 0.1M-sodium phosphate buffer, pH 6.5 containing 5mM-cysteine, 40mM-2-mercaptoethanol and 2mM-EDTA at 10,000 rpm for 5 min. 2. The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography, and the purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. 3. The specific activity of purified enzyme was 29.65 unit/mg protein and the yield was 7.22%. 4. The moecular weight of the protease was estimated to be about 51,000 by SDS-polyacrylamide gel electrophoresis, and the enzyme had Km value of 54.5 mg/ml for casein. 5. The purified enzyme had a maximum activity at pH 6.0 and $50^{\circ}C$, and was stable from pH 5.5-6.5 and at temperatures below $50^{\circ}C$ 6. Casein was a better substrate for this protease compared to hemoglobin. 7. The enzyme activity was markedly inhibited by p-chloromercuribenzoic acid and heavy metal salts such as $HgCl_2$ and $MnSO_4$ also considerably inhibited the enzyme activity.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.705-711
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• 2005

The reaction of lauric acid vinyl ester with n-butanol was established to give lauric acid butyl ester by subtilisin A-catalyzed transesterification in organic media containing nonionic surfactants. Pyridine has been used as an organic solvent since it provides higher yields than other organic solvents. However, because of stench of pyridine, compounds enzymatically synthesized in pyridine may be unsuitable as ingredients for foods and drugs. Hence, in order to select an organic solvent to replace pyridine, sugar esters were synthesized with the protease in various organic media. However, no solvent paralleled pyridine in yields. On the basis of this result, pyridine-based W/O microemulsions containing nonionic surfactants and water were used in enzymatic synthesis of the sugar ester, and when Tween 60, Brij 56, or 1-O-octyl-${\beta}$-D-glucopyranose was used for the W/O microemulsions, the yield was higher.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.377-388
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• 2005

Effects of silkworm powder addition on rheological properties of dough and quality characteristics of bread were investigated. Protein content of silkworm powder was 53,98%, much higher than 12.46% of wheat powder, Crude fiber, fat, and pretense contents of silkworm powder were higher than those of wheat flour, Acid analysis revealed glutamic acid content was highest 4,046.16 mg thus, significant depreciation of breadmaking was expected due to weakened gluten structure or dough. Addition of silkworm powder(optimum at 2%) with pretense inactivated by heat treatment resulted in significant improvement of volume and bread quality, with external and internal scores close to those of the control.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.130-136
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• 2011

Five strains of Actinomyces were isolated from freshwater sponges, Baikalospongia and Lubomirskia, in Lake Baikal. By 16S rRNA sequencing, isolates were identified as Streptomyces griseoplanus, S. halstedii, S. violascens, S. flavovirens, and S. microflavus. Isolates had different characteristics of growth temperature, carbon utilization, enzyme activity, and cellular fatty acid composition. Optimum growth conditions of isolates were $30-37^{\circ}C$, pH 8-9, and 0-1.5% salt concentrations. Major fatty acid compositions were anteiso-$C_{15:0}$, iso-$C_{15:0}$, and iso-$C_{16:0}$. Strain ATS-BA-19 had DNase and chitinase activities and strain ATS-BA-16 had cellulase and protease activities. Colonies of strain ATS-BA-15 and ATS-BA-19 made inhibition zone of Pseudomonas aeruginosa.

• Journal of Pharmaceutical Investigation
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• v.22 no.2
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• pp.97-104
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• 1992

The purpose of this study was (i) to determine whether protease inhibition by medium chain fatty acids such as sodium caprate, sodium caprylate and sodium laurate led to suppression of insulin proteolysis over a range of insulin concentrations and (ii) elucidate preventing effect of the enhancers on molecular self-association of insulin in pH 7.4 phosphate buffer isotonic solution. To this end, the rate of insulin proteolysis in nasal tissue supernatants of the albino rabbits was determined in the presence of $0.1{\sim}2%$ sodium caprylate, sodium caprate and sodium laurate at insulin concentrations ranging from $5\;to\;100\;{\mu}M$. At fatty acid salts concentration lower than 0.5%, insulin proteolysis was accelerated but the enhancers of high concentration (>1%) reduced the rate of insulin proteolysis. These effects were dependent upon insulin concentration and chain length of fatty acid salts. Circular dichroism spectra of insulin solutions were then determined. Monomer fraction of insulin was increased with increasing sodium caprate. Therefore, half-life decrease of insulin at low concentrations of the enhancers was attributed to deaggregation of insulin by the enhancers, increasing the proportion of monomers available for nasal proteolysis. And the increase of half-life at high concentration of the enhancers was attributed to inhibitory effect on protease rather than the effect of monomer fraction.

• Microbiology and Biotechnology Letters
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• v.2 no.1
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• pp.13-17
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• 1974

A strain of Streptomyces sp. which producing a metal containing proteolytic enzyme was isolated from soil and some properties of this enzyme were investigated. The following results were obtained. 1. Optimal pH and temperature of this enzyme were pH7.0 and 37$^{\circ}C$ 2. This enzyme was easily inactivated with heat treatment: for example, by the treatmentat 37$^{\circ}C$ for 100 minutes the activity of the enzyme was decreased to about 50 per cent of intial actively but this enzyme was stable at neutral pH. 3. The activity of this enzyme was not inhibited by $Mg^{＋＋}$, $_Mn^{＋＋}$, $Ca^{＋＋}$, Pb$^{＋＋}$, or $Ba^{＋＋}$ ect. but strongly inhibited by Hg$^{＋＋}$, Co$^{＋＋}$, Ag$^{＋}$, Cu$^{＋＋}$, or Cd$^{＋＋}$. 4. This enzyme was strongly inhibited by EDTA but was not inhibited by oxalic acid, citric acid, 2, 4-dinitrophenol, $\varepsilon$-aminocaproic acid, cysteine, or thiourea.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.72-79
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• 2005

A new Bacillus peptidase, bacillopeptidase DJ-2 (bpDJ-2), with molecular mass of 42 kDa and isoelectric point (pI) of 3.5- 3.7, was purified to homogeneity from Bacillus sp. DJ-2 isolated from Doen-Jang, a traditional Korean soybean fermented food. The enzyme was identified as an extracellular serine fibrinolytic protease. The optimal conditions for the reaction were pH 9.0 and $60^{\circ}C$. The first 18 amino acid residues of the N-terminal amino acid sequence of bpDJ-2 were TDGVEWNVDQIDAPKAW, which is identical to that of bacillopeptidase F (bpf). However, based on their Nterminal amino acid sequence, molecular size, and pI, it is different from that of bpf and extracellular 90 kDa. The whole (2,541 bp, full-bpDJ-2) and mature (1,956 bp, mature-bpDJ-2) genes were cloned, and its nucleotide sequence and deduced amino acid sequence were determined. The expressed proteins, full-bpDJ-2 and mature-bpDJ-2, were detected on SDSPAGE at expected sizes of 92 and 68 kDa, respectively.

• Korean journal of applied entomology
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• v.30 no.3
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• pp.180-186
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• 1991

This study was carried out to acquire some basic biochemical informations on the granulosis virus(GV) of Pieris rapae and Pieris brassicae. The capsule protein was composed of a single polypeptide with a molecular weight of 30,000 dalton for P. rapae GV and 31,000 dalton for P. brassicae GV. The major amino acids of capsule protein were glutamic acid, aspartic acid and lysine. When the capsule protein was partially digested with trypsin, chymotrypsin, papain or Staphylococcus aureus V8 protease, the digested products of the two viruses showed no difference in electrophoretic mobility. The patterns of the polypeptides of the two virus particle on SOS-polyacrylamide gel showed a little difference in high molecular weight region(over MW 100 kd).

• Applied Biological Chemistry
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• v.47 no.2
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• pp.176-181
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• 2004

This study was carried out to investigate the effect of yucca extract on the quality characteristics of Chungkookjang using Bacillus subtilis p01. The changes in the contents of amino-type N, ammonia type N, volatile compounds and organic acids, and those in the activities of ${\alpha}-amylase$ and protease were also determined during aging of Chungkookjang. The amount of amino-type N increased gradually with time for aging. The content of amino-type N was slightly higher in Chungkookjang fermented by adding yucca extract than in the control without yucca extract. The content of ammonia-type N was slightly lower in Chungkookjang with yucca extract than in the control without yucca extract. The activities of amylase and protease were higher in Chungkookjang with yucca extract than in the control and the highest in Chungkookjang containing 0.5 mg/g of yucca extract. Organic acid contents in Chungkookjang was the highest at the initial period of fermentation. The contents of organic acids in Chungkookjang with yucca extract was higher than that in control for 48 hr of aging. The amounts of 2,5-dimethylpyrazine were increased by addition of yucca extract, while those of cis-3-hexanol were decreased.