• Food Science and Biotechnology
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• v.17 no.4
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• pp.766-771
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• 2008

The proteolytic enzyme from Saccharomyces sp. B101 was purified to homogeneity by ammonium sulfate fractionation, ultrafiltration, diethyl aminoethyl (DEAE)-Sephadex A-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography from the culture supernatant of Saccharomyces sp. B101. The specific activity and the purification fold of the purified enzyme were 4,688.9 unit/mg and 18, respectively. The molecular weight of the purified enzyme was estimated to be 33 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature for the enzyme activity were pH 8.5 and $30^{\circ}C$, respectively. The enzyme activity was relatively stable in the pH range of 6.5-8.5 at below $35^{\circ}C$. The salt-tolerance and stability for the enzyme activity were relatively stable even at NaCl concentrations of 10 and 15%. The activity of enzyme was inhibited by $Ag^{2+}$ and $Fe^{2+}$, and activated by $Mn^{2+}$. In addition, the enzyme activity was potently inhibited by ethylenediaminetetraacetic acid (EDTA) and phenylmethyl sulfonylfluoride (PMSF). Based on these findings we concluded that the purified enzyme was a serine protease. Km and Vmax values for hammastein milk casein were 1.02 mg/mL and 278.38 unit/mL, respectively.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.457-462
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• 2008

Lactococcus lactis NK34, isolated from jeotgal (Korean traditional fermented fish), produces bacteriocin against bovine mastitis pathogens such as Staphylococcus aureus 7, S. aureus 8, Staphylococcus chromogenes 10, S. chromogenes 19, Staphylococcus hominis 9, Streptococcus uberis E290, Enterococcus faecium E372, Streptococcus agalactiae ATCC 13813, Pseudonocardia autotrophia KCTC 9455, and Staphylococcus simulans 78. Lacticin NK34 was inactivated by protease XIV but not by protease IX, protease XIII, proteinase K, $\acute{a}$-chymotrypsin, trypsin, and pepsin. Also, lacticin NK34 was stable over a pH range of 2 to 9 for 4 hr and withstood exposure to temperatures of 30-$100^{\circ}C$ for 30 min. Lacticin NK34 showed bactericidal effects against S. simulans 78. This bacteriocin was purified using ammonium sulfate precipitation, ion exchange chromatography, ultrafiltration, and hydrophobic chromatography. Tricin-SDS-PAGE of purified bacteriocin gave the same molecular weight (3.5 kDa) as nisin. The gene encoding this bacteriocin was amplified by PCR using nisin gene-specific primers. It showed similar sequences to this nisin Z gene. These results indicate that lacticin NK34 is a nisin-like bacteriocin, and could be used as an antimicrobial alternative for livestock.

• Food Science and Biotechnology
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• v.14 no.3
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• pp.375-379
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• 2005

Physicochemical properties, intestinal microbial growth, and inhibitory effects of alcohol-insoluble polysaccharide (AIP) extracted from cucumber peel were investigated. AIP was composed of 14.54% crude protein, 1.04% crude lipid, 13.74 % crude ash, 9.1% soluble dietary fiber, and 41.2% insoluble dietary fiber. AIP showed low bulk density (0.18 g/mL) and water-holding capacity (6.39 g/g), and high oil-holding capacity (3.96 g/g). Pectic substance fractions [water-soluble pectic substance (WSP), ethylenediaminetetraacetic acid-soluble pectic substance (ESP), and alkali-soluble pectic substances (ASP)] and hemicellulose fractions [1 M KOH-soluble hemicellulose (KHP1) and 4 M KOH-soluble hemicellulose (KHP4)] were obtained from sequential chemical fractionation of AIP. WSP showed higher total sugar contents than total uronic acid contents, whereas opposite results were observed in ESP and ASP. Molecular weight distributions of three pectic substance fractions were in order of ASP>ESP>WSP. Ion exchange chromatogram pattern of WSP was different from those of ESP and ASP. Major component of WSP was fraction eluted by 0.05 M ammonium acetate buffer, whereas that of ESP and ASP was fraction eluted by 0.2 M NaOH. WSP and ASP showed growth-promoting activities against Lactobacillus brevis, Bifidobacterium bifidum, and B. longum, whereas B. bifidum and B. longum for ESP. KHP1 and KHP4 fractions had significant growth-promoting activities against B. bifidum.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.111-116
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• 1996

Polyphenol oxidase(PPO) isolated from the crude extract of ascidian, Halocynthia roretzi, showed higher affinity for catechol than tyrosine or DL-DOPA. Successful enzyme assay could be performed at $25^{\circ}C$, 10min. by mixing 0.2ml of crude enzyme extract with 2.8ml of 0.13M catechol in 0.1M sodium phosphate buffer(pH 6.4). The specific activity of PPO which had been purified with a combination of ammonium sulfate treatment, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B was 13-fold disc gel electrophoresis. The activity of PPO was stable from pH 5.0 to 8.0 and showed the peak activity at pH 6.4 .The optimum reaction temperature for PPO oxidation on catechol was 35$^{\circ}C$ and those enzyme were heat stable up to 4$0^{\circ}C$. Molecular weigth of the enzyme was estimated about 170kDa. One molecule was found to be composed of gour subunits. Two of them had molecular weigh of 55kDa and the others 30kDa. The {TEX}$K_{m}${/TEX} values, {TEX}$V_{max}${/TEX} and catalytic efficiency({TEX}$V_{max}${/TEX}/{TEX}$K_{m}${/TEX}) for catechol were 0.12mM, 2.5mM/liter/min. and {TEX}$0.18min^{-1}${/TEX} respectively. The substrate affinity and electrophorectic pattern suggested that the enzyme of ascidian was considered to be not tyosine but catechol oxidase.

• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.46-50
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• 1996

Monoanionic nickel(Ⅲ) complexes, [Ni(dmbit)2]1- and [Ni(dmbbip)2]1- where dmbit2- and dmbbip2- denote 2-thiobenzo[d]-1,3-dithiole-5,6-dithiolate and 1,2-bis(isopropylthio)benzen-4,5-dithiolate, respectively, have been synthesized by the iodine oxidation of dianionic complexes. In the scanning electron microscopic(SEM) images, these complexes show the well-grown two-dimensional layered structures which are clearly comparable to the dianionic ones with three-dimensional structures. Magnetic susceptibilities of nickel(Ⅲ)complexes are fitted well with the two-dimensional Heisenberg antiferromagnet model of S=1/2 system resulting in the spin-exchange parameters (|J|/k) of 11.4 K and 0.45 K, respectively. The weaker magnetic interaction in [Ni(dmbbip)2]1- is resulted from the bulky isopropyl groups on the periphery of dmbbip ligand. EPR measurements for [Ni(dmbit)2]1- give the signal with axial symmetry and the anisotropic g-values for low-spin nickel(Ⅲ) (g//=2.158, g =2.030,gav=2.074 at 300 K; g//=2.162, g =2.038, gav=2.080 at 77 K). It is therefore concluded that nickel(Ⅱ) is oxidized to nickel(Ⅲ), rather than dmbit2- and dmbbip2- ligands are, by the iodine oxidation. The paramagnetic Ni(Ⅲ) would be located in the axial symmetry(D4h) with the electronic configuration of (dxz2dyz2dz22dxy1dx2-y20).

• Korean Journal of Agricultural Science
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• v.18 no.1
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• pp.49-73
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• 1991

To elucidate enzymatic properties of $\alpha$-galactosidases (EC3, 2, 1, 22) from germinated soybean and Aspergillus niger changes in the enzyme activities and oligosaccharide contents during germination of soybean were determined and $\alpha$-galactosidases from germinated soybean and wheat bran culture of Aspergillus niger were purified by ammonium sulfate fractionation, ion exchange chromatography and gel filtration. Their chemical and enzymatic properties were investigated and the results obtained were summarized as follows : 1. $\alpha$-Galactosidase activity of soybean was maximized when it was germinated at $25^{\circ}C$ for 120 hours. And raffinose and stachyose in soybean were decomposed completely after 96 hours and 120 hours of germination, respectively. 2. The highest level of $\alpha$-Galactosidase activity was obtained when Aspergillus niger was grown on wheat bran medium at $30^{\circ}C$ for 96 hours. 3. Soybean $\alpha$-galactosidase was purified by 6.6 fold by ammonium slufate fractionation, ion exchange chromatography on DEAE-Cellulose and Sephadex A-50., and gel filtration on Sephadex G-150. Its specific activity was 825 units/mg protein and the yield was 2.5% of the total activity of crude extracts. 4. Aspergillus niger $\alpha$-galactosidase was purified by 23.7 fold. Its specific activity was 1,229 units/mg protein and the yield was 14% of the total activity of wheat bran culture. 5. The purified $\alpha$-galactosidases of soybean and Aspergillus niger were found to be homogeneous by polyacrylamide gel electrophoresis and by HPLC. 6. Chemical properties of the purified $\alpha$-galactosidases were : 1) The soybean $\alpha$-galactosidase was monomeric and its molecular weight was estimated to be 30,000 by SDS-PAGE whereas the Aspergillus niger $\alpha$-galactosidase was a tetrameric glycoprotein which consisted of identical subunits with molecular weight of 28,000 each.

• Journal of the Mineralogical Society of Korea
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• v.16 no.2
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• pp.135-149
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• 2003

Domestic zeolite ores are mostly composed of Ca-type clinoptilolite, accompanying a little amounts of mordenite. However, other types of zeolite ores rich in ferrierite, heulandite, or mordenite are less commonly found. Based on the quantitative XRD analysis, zeolite contents are determined to be nearly 50∼90 wt%. Impurities (mostly ＞ 10 wt%) in the zeolite ores chiefly consist of quartz, feldspar, smectite, and opal-CT. The determined CEC values ($CEC_{AA}$ ) of powdery samples (grain size: < 125 $\mu\textrm{m}$) of zeolite ores by the Ammonium Acetate method are mostly higher than 100 meq/100 g. Some zeolites from the Guryongpo area, corresponding to the clinoptilolite ore, are measured to be dominantly high in CEC values ranging 170∼190 meq/100 g. Cation exchange property of the zeolite ores varies greatly depending on the types or zeolite species present in the ores. Despite of the lower grade in zeolite content, the $CEC_{AA}$ of ferrierite ore is comparatively high. Compared to this, the $CEC_{AA }$ of heulandite ore is very low, though the zeolite ore exhibits the highest grade ranging up to about 90 wt%. In addition, the CEC values calculated theoretically from the framework composition of clinoptilolite-heulandite series are not consistent with those determined by the cation exchage experiment. The measured $CEC_{AA}$ of clinoptilolite ores are generally higher than those of heulandite ores. This may be due to the higher Ca abundance in exchangeable cation composition and the presence of probable stacking faults in heulandite. The variation of $CEC_{CEC}$ is roughly proportional, though not strictly compatible, to the zeolite contents in clinoptilolite ores. It seems to be caused by the fact that the $CEC_{AA}$ of clinoptilolite locally varies depending on crystal-chemical diversity, i. e., the variation in framework composition (Si/Al) and exchangeable cation composition (especially, the contents of Ca and K). In addition, the determined CEC values ($CEC_{MB}$ ) of zeolite ores by the Methylene Blue method are much higher than those calculated from smectite contents. It suggests a probable reaction of Methylene Blue ion ($C_{16}$ $H_{18}$ $N_3$S+) with larger-pore zeolites than clinoptlolite-heulandite series, i.e., ferrierite and mordenite as well as with smectite. This can be supported by the fact that the ferrierite ore accompanying little amount of smectite has the highest value in CE $C_{MB}$ .

• Journal of the Mineralogical Society of Korea
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• v.16 no.3
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• pp.201-213
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• 2003

The adsorption property and ability of domestic zeolites for some heavy metal ions (Ag, Pb, Cr, Cu, Zn, Mn), which may cause a serious environmental problem in industrial wastewater, were evaluated on ore unit through a series of adsorption experiments together with careful examinations of mineral composition and properties of the zeolites. Though the adsorption behavior basically took place in the form of a cation exchange reaction, the higher CEC value does not necessarily to imply the higher adsorption capacity for a specific heavy metal. A general trend of the adsorption selectivity for heavy metals in the zeolites is determined to be as follow: $Ag\geq$Pb>Cr,Cu$\geq$Zn>Mn, but the adsorption properties of heavy metal ions somewhat depend on the species and composition of zeolite. Clinoptilolite tends to adsorb selectively Cu in case of Cr and Cu, whereas heulandite prefers Cr to Cu. A dominant adsorption selectivity of the zeolite ores for Ag and Pb is generally conspicuous regardless of their zeolite species and composition. The zeolite ores exhibit a preferential adsorption especially for $Ag^{+}$ so as not to regenerate when treated with $Na^{+}$ . In the adsorption capacity for heavy meta ions, the zeolites differ in great depending on their species: ferrierite>clinoptilolite>heulandite. Considering the CEC value of mordenite, the mordenite-rich ore appears to be similar to the clinoptilolite ore in the adsorption capacity. The adsorption capacity for heavy metals is not positively proportional to the CEC values of the zeolites measured by the exchange reaction with ammonium ion. In addition, the adsorption capacity roughly tends to depend on the zeolite contents, i.e., the grade of zeolite ore, but the trend is not consistent at all in some ores. These may be caused by the adsorption selectivity for some specific heavy metals, the presence of possible stacking micro-faults and natural cations such as K hardly to exchange in the zeolite. Considering the economic availability and functional effectiveness as natural zeolite resources, clinoptilolite ores could be applicable to utilize the domestic zeolites for the removal of heavy metals.

• Korean Journal of Poultry Science
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• v.20 no.2
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• pp.65-72
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• 1993

The experiment was conducted to estasblish the large scale production of anti-serum against chicken IgG and to profile the developmental changes of serum IgG levels during all the feeding period(from hatching to 7 weeks of age) in broiler chicks. Blood sample were taken from Hubbard chicken hi-daily or /and weekly during the experimental period. The pure IgG was isolated from ammonium sulfate treated chicken serum by ion exchange chromatography. The quantitative assay of serum IgG were carried by RID method. It was observed that IgG concentrations were showed the highest at hatching(4.25 $m\ell$/$m\ell$), after that dicreased rapidly, lowest at 2 weeks of age(0.81 $m\ell$/$m\ell$), and gradually increased to 7 weeks of age (2.48 $m\ell$/$m\ell$) There was no differences of IgG level between sex, but the IgG levels of male chicks dicreased more rapidly and increased earlier thereafter than those of females during the first two weeks of agg.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.515-522
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• 1998

Plant root rotting fungi, Fusarium solani are suppressed their growth by the chitinase which is produced from the antagonistic soil bacteria. The chitinase producable antagonistic bacterium Pseudomonas sp. 3098 was selected as a powerful biocontrol agent of F. solani from ginseng rhizosphere. The antagonistic Pseudomonas sp. 3098 was able to produce a large amount of extracellular chitinase which is key enzyme in the decomposition of fusarial hypal walls. The chitinase was purified from cultural filtrate of Pseudomonas sp. 3098 by the procedure of ammonium sulfate precipitation, anion exchange chromatography, gel filtration on Bio-Gel P-100, and 1st and 2nd hydroxyapatite chromatography. The molecular mass of the purified enzyme was ca. 45 kDa on SDS-FAGE. The optimal pH and temperature for the activity of purified chitinase were 5.0 and 45$^{\circ}C$, respectively. The enzyme was stable in pH range of 5.0 to 9.0 up to 5$0^{\circ}C$ The enzyme was significantly inhibited by metal compounds such as FeCl$_2$, AgNO$_3$ and HgCl$_2$, and was slightly inhibited by p-CMB, iodoacetic acid, urea, 2,4-DNP and EDTA. The enzyme had ability of digestion on colloidal chitin and chitin from shrimp shell, but could not digest chitosan and chitin from crab shell. Km value of the enzyme was 0.11% on colloidal chitin, and the maximum hydrolysis rate of the enzyme was 34% on colloidal chitin.