• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.439-446
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• 2020

Two Bacillus strains, K3 and K208, both demonstrating strong fibrinolytic activities were isolated from Kimchi, a traditional Korean preparation of fermented vegetables. Isolates were subjected to various molecular biology based identification methods including RAPD-PCR and identified as B. subtilis and B. velezensis, respectively. Tryptic soy broth (TSB) was found to best maintain both the growth and the fibrinolytic activity of these strains. Culture supernatants were analyzed by SDS-PAGE and fibrin zymography, and the results indicate that a 40 and 27 kDa band seem to be responsible for the fibrinolytic activities of these two isolates and the 27 kDa band was subsequently identified as the mature form of AprE, the major fibrinolytic enzyme. Thus the aprE genes were cloned and the translated amino acid sequences demonstrated 99.3% identity with each other, and 86.5% identity with BsfA, a fibrinolytic enzyme from B. subtilis ZA400 also isolated from Kimchi, and AprE2, a fibrinolytic enzyme from B. subtilis CH3-5 isolated from Cheonggukjang, a traditional Korean fermented soy. Given this B. subtilis K3 and B. velezensis K208 may be promising starter cultures in the production of fermented foods.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.87-91
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• 1995

The chitinase gene was cloned from Acinetobacter sp. WC-17 for investigating the genetic control and enzymatic properties of bacterial chitinase. A genomic library of Acinetobacter sp. WC-17 was prepared in E.coli JM109 by using pUC18 as a vector. The chitinase-positive clone containing 3.2kb insert fragment was obtained from 5, 000 insert-bearing transformants. The optimum pH and temperature of cloned enzyme were 6.0 and $55^{\circ}C$, respectively. Almost all the chitinase activity of E.coli recombinant was localized in the periplasmic fraction, while most of the enzyme activity of Acinetobacter sp. WC-17 was found in the extracellular fraction.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.165-168
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• 1993

In order to know the enzyme activities of Filbricola seouzenis, an intestinal trematode of human and rodent in Korea. the enzyme histochemical method is applicated. Activities of acid phosphatase (E.C.3.1.3.2) and non-specific esterase (E.C.3.1.1) were present in microvilli and glandular cells of trlbocytic organ and the epithelium of the caecum.

• Journal of Animal Science and Technology
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• v.63 no.1
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• pp.69-76
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• 2021

This experiment was conducted to evaluate the effect of supplementing enzyme cocktail on growth performance, digestibility of nutrients, and monosaccharide concentration in ileum and ceca of broiler chickens fed wheat-based diets. A total of 600 male broilers (42.26 ± 1.76 g, 0 day old) were used for 35 days of feeding trial consisting of 2 phases (starter phase from d 0 to 21 and finisher phase from d 21 to 35). Four dietary treatments were prepared based on wheat diets containing four levels of enzyme cocktail supplementation at 0, 0.2, 0.3, and 20 g/kg. Overall, dietary enzyme cocktail supplementation decreased feed conversion ratio (linear p = 0.007; quadratic p = 0.013) and improved (linear p < 0.05) the apparent ileal digestibility of dry matter (DM), crude protein, and soluble and insoluble non-starch polysaccharides. The apparent total tract digestibility of DM and gross energy were increased (linear p < 0.01) with increasing supplementation levels of the dietary enzyme cocktail. The concentrations of arabinose, xylose, mannose, and glucose in ileal digesta were linearly increased (p < 0.01) with increasing enzyme cocktail supplementation levels. In addition, the quadratic effect was observed (quadratic p = 0.046) in mannose concentration of ileal digesta. The concentration of arabinose, xylose, mannose, and galactose in cecal digesta was increased (linear p < 0.05) with increasing dietary enzyme cocktail supplementation levels. The supplementation of enzyme cocktail efficiently increased the utilization of nutrients in broiler and there was no adverse effects of high dosage supplementation level.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.316-320
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• 1996

An alkaline proteinase produced by Yarrowia lipolytica TH65 was purified by 40-65% ammonium sulfate fractionation, DEAE-cellulose chromatography, and gel filtration with Sephadex G-100 and Sephadex G-75. The purified enzyme was shown as a single band on SDS-PAGE, and its molecular weight 31,500. Optimum temperature and pH were 40$\circ$C and 8.5-9.0, respectively, and the enzyme was stable below 40$\circ$C and in the pH range of 6-8. The enzyme was strongly inhibited by divalent ions, completely by PMSF, and partially by EDTA, EGTA, and phenanthroline. But the inhibitory effect in the presence of EDTA, EGTA and phenanthroline could be reversed by addition of Ca$^{2+}$. Thus, these results indicated that the purified enzyme was an alkaline serine proteinase (E.C. 3.4.21.14).

• Bulletin of the Korean Chemical Society
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• v.3 no.3
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• pp.122-129
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• 1982

In order to extend our understanding on the multiple inhibition enzyme kinetics, a general equation of an enzyme reaction in the presence of two different reversible inhibitors was derived by what we call "match-box mechanism" under the combined assumption of steady-state and quasi-equilibrium for inhibitor binding. Graphical methods were proposed to analyze the multiple inhibition of an enzyme by any given sets of different inhibitors, i.e., competitive, noncompetitive, and uncompetitive inhibitors. This method not only gives an interaction factor $({\alpha})$ between two inhibitors, but also discerns ${\alpha}_1$ and ${\alpha}_2$ with and without substrate binding, respectively. The factors involved in the dissociation constants of inhibitors can also be evaluated by the present plot. It is also shown that the present kinetic approach can be extended to other forms of activators or hydrogen ions with some modification.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.242-248
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• 2002

Previously, it was reported that the nonhomologous C-terminal regions of the D-hydantoinases are nonessential for catalysis, but affect the oligomeric structure of the enzyme [3]. In an effort to further confirm the above observation, the C-terminal region-inserted enzyme was constructed by attaching a peptide (22 residues) at the C-terminal of the D-hydantoinase from Bacillus thermocatenulatus GH2, and its structural and biochemical properties were compared with both the wild-type and C-terminal region-truncated enzymes. As a result, native tetrameric D-hydantoinase was dimerized as the truncated enzyme, and the inserted mutant with a new sequence was expressed as a catalytically active form in E. coli. Expression level of the inserted and truncated enzymes were found to be significantly increased compared to the level of the wild-type enzyme, and this appears to be due to the reduced toxic effect of the mutant enzymes on host cells. Dimerized enzymes exhibited increased thermo- and pH stabilities considerably when compared with the corresponding wild-type enzyme. Comparison of the substrate specificity between the mutant and wild-type enzymes suggests that the substrate specificity of the D-hydantoinase is closely linked with the oligomeric structure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1189-1196
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• 1998

The antiatherogenic effect of kimchi ingredients was studied in terms of antioxidative effect against Newzealand white rabbits that fed 1% cholesterol. Experimental groups was fed 8% Baechu (Brassica pekiinensis), or 1% red pepper(Capsium annum), or 1% garlic(Allium sativum) for 12 weeks. Blood samples were drawn every 2 weeks to analyze vitamin E, POV, and TBARS. Hepatic antioxidative enzyme activity, vitamin E, and carotene concentration also were measured. Plasma TBARS and POV level were markedly lowered in both red pepper and garlic fed rabbits(p<0.05) compared to control. Hepatic POV and protein carbonyl values were lowered in the rabbits fed kimchi ingredients compared to control(p<0.05). Plasma vitamin E concentration was increased in the rabbits fed red pepper and garlic compared to control(p<0.05). Hepatic vitamin E concentration was increased in red pepper and garlicfed rabbits compared to control. For the hepatic antioxidative enzyme acitivity, catalase activity was significantly increased in red pepper and garlic fed rabbits compared to control. Therefore, Baechu, red pepper, and garlic exert an antioxidative effect against rabbits fed 1% cholesterol for 3 months.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.550-555
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• 1995

A strain of Pseudomonas sp. isolated from soil was shown to produce a high level of extracellular endo-inulinase. In this work, the endo-inulinase gene (inu1) of the bacterial strain was cloned into the plasmid pBR322 by using EcoRI restriction endonuclease and E. coli HB101 as a host strain. One out of 7, 000 transformants obtained from the above cloning experiment formed a clear zone around its colony on the selective medium supplemented with 2.0% inulin after a prolonged incubation at 37$\circ$C and subsequent cold shock treatment. The functional clone was found to carry a recombinant plasmid (pKMG50) with a 3.7 kb genomic insert containing the genetic information for the inulinase activity. The inulinase from E. coli HB101/pKMG50 was proved to be an endo-acting enzyme and produced constitutively in the recombinant E. coli cells. Zymogram of the enzyme from the recombinant cells with inulin substrate indicated that the molecular mass of the active protein was 190 Kd, while that of the endo-inulinase from the Pseudomonas strain was 170 Kd. This size discrepancy suggested that the inulinase from the recombinant E. coli HB101 cells might be the initial product of translation, not the mature form produced in the strain of Pseudomonas sp..

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1810-1818
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• 2015

For the synthesis of various pharmaceuticals, chiral alcohols are useful intermediates. Among them, (R)-ethyl-4-chloro-3-hydroxybutanoate ((R)-ECHB) is an important building block for the synthesis of L-carnitine. (R)-ECHB is produced from ethyl-4-chloro-3-oxobutanoate (ECOB) by a reductase-mediated, enantioselective reduction reaction. The Saccharomyces cerevisiae YOL151W reductase that is expressed in Escherichia coli cells exhibited an enantioselective reduction reaction toward ECOB. By virtue of the C-terminal His-tag, the YOL151W reductase was purified from the cell-free extract using Ni²⁺-NTA column chromatography and immobilized onto Ni²⁺-magnetic microparticles. The physical properties of the immobilized reductase (Imm-Red) were measured using electron microscopy, a magnetic property measurement system, and a zeta potential system; the average size of the particles was approximately 1 μm and the saturated magnetic value was 31.76 emu/g. A neodymium magnet was used to recover the immobilized enzyme within 2 min. The Imm-Red showed an optimum temperature at 45℃ and an optimum pH at 6.0. In addition, Bacillus megaterium glucose dehydrogenase (GDH) was produced in the E. coli cells and was used in the coupling reaction to regenerate the NADPH cofactor. The reduction/oxidation coupling reaction composed of the Imm-Red and GDH converted 20 mM ECOB exclusively into (R)-ECHB with an e.e._p value of 98%.