Jong-Hee Kim

Myongji University, Sŏul, Seoul, South Korea

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Publications (8)6.12 Total impact

  • Jong-Hee Kim, Soon-Kwang Hong
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    ABSTRACT: The objective of this study was to address the issues associated with the solubility of the pork meat oligopeptide, while maintaining its original nutritional value and improving its digestibility. The pork meat oligopeptide was used to produce an oral liquid supplement that was contained in a 200 can. The formulation was designed to satisfy 20% of the daily recommended nutrition intake of an adult male aged between 20 and 29. Analysis of the quality characteristics showed that this formulation was highly homogenized as an oral liquid supplement with advanced solubility. In addition, based on the viscosity, pH, color value, turbidity, and brix, the product was shown to advanced processing quality with great solubility; however, there was some concern that the taste would be deteriorated due to the bitter taste of the peptide. Thus, further studies need to be performed before this formulation can be commercialized.
    The Korean Journal of Food And Nutrition. 01/2012; 25(1).
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    ABSTRACT: Production of proteins in secretary form is one of the important factors affecting fermentation. The Tat (twin arginine translocation) protein secretion system, which includes the proteins TatA, TatB, and TatC, was identified in the genomic sequence of Streptomyces griseus IFO13350. The tatA and tatC genes were organized into a polycistronic operon, whereas tatB was located separately on the chromosome. Comparison of amino acid sequences suggested that TatC was a membrane-spanning protein, whereas TatA and TatB were found to be cytoplasmic proteins. Analysis of extracellular proteins and N-terminal amino acid sequencing revealed that secretion of SGR5556 was significantly enhanced by overexpression of TatAC in S. griseus HH1. Further, enzymatic study showed that SGR5556 encoded a glycerophosphoryl diester phosphodiesterase. In addition, other hydrolase activities, such as those of amylase, total protease, metalloprotease, trypsin, chymotrypsin, and Leuaminopeptidase, were also enhanced by 3, 3, 2.6, 2.3, 5.4, and 2.5 fold, respectively, in S. griseus upon TatAC overexpression. Overexpression of TatAC induced the production of a greenish-yellow pigment in S. griseus HH1 as well as more abundant sporulation at an earlier stage in Streptomyces coelicolor A3(2). In silico analysis by TatFIND, SignalP, and TMHMM identified 19 binding proteins, 28 enzymatic proteins, and 27 other proteins with unknown functions as putative TatAC-dependent secretary proteins. These results clearly indicate that TatA and TatC constitute a functional Tat system in S. griseus. Additionally, the S. griseus Tat system can be useful for the production of valuable proteins, including many hydrolytic enzymes and candidates of Tat-dependent secretary proteins, under industrial conditions. KeywordstatA–tatB–tatC–twin-arginine pathway– Streptomyces griseus
    Biotechnology and Bioprocess Engineering 01/2011; 16(1):59-71. · 1.28 Impact Factor
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    ABSTRACT: The chemical compositions, and antibacterial and antifungal effects of essential oils extracted from three coniferous species, Pinus densiflora, Cryptomeria japonica, and Chamaecyparis obtusa, were investigated. Gas chromatography mass analysis of the essential oils revealed that the major components and the percentage of each essential oil were 16.66% beta-phellandrene and 14.85% alpha-pinene in P. densiflora; 31.45% kaur-16-ene and 11.06% sabinene in C. japonica; and 18.75% bicyclo [2, 2, 1] heptan-2-ol and 17.41% 2-carene in Ch. obtusa. The antimicrobial assay by agar disc diffusion method showed that 2.2 microg of Ch. obtusa oil inhibited most effectively the growth of Escherichia coli ATCC 33312 and Klebsiella oxytoca ATCC 10031, whereas the C. japonica oil gave weak antimicrobial activity. The minimal inhibitory concentration (MIC) values for bacterial strains were in the range of 5.45-21.8 mg/ml depending on essential oils, but most Gram-negative bacteria were resistant even at 21.8 mg oil/ml. P. densiflora oil showed the most effective antifungal activity and the MIC values for Cryptococcus neoformans B42419 and Candida glabrata YFCC 062CCM 11658 were as low as 0.545 and 2.18 mg/ml, respectively. Cryp. neoformans B42419 was the most sensitive to all essential oils in the range of 0.545-2.18 mg/ml. Our data clearly showed that the essential oils from the three conifers had effective antimicrobial activity, especially against fungi.
    Journal of Microbiology and Biotechnology 05/2009; 19(4):391-6. · 1.40 Impact Factor
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    Jong-Hee Kim, Soon-Kwang Hong
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    ABSTRACT: In this study, pork meat oligopeptides and ISP oligopeptides were prepared from purified meat protein and, isolated soybean protein, respectively. These oligopeptides were added to porridge. Then their manufacturing suitability and quality characteristics were evaluated. The porridge which included meat oligopeptides and ISP oligopeptides satisfied the 20% RI (recommended intake) of protein and 40% RI of EAA for man between the ages of 20 to 29. According to measurements of the physicochemical characteristics of porridge, the degree of viscosity, spreadability, pH, and lightness L value, were acceptable for consumption. In addition, the oligopeptide powders had good solubility. and were easy to add when cooking. The above results indicate that pork meat oligopeptides and ISP oligopeptides are excellent dietary nitrogen sources for a variety of applications.
    The Korean Journal of Food And Nutrition. 01/2009; 22(4).
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    Jong-Hee Kim, Soon-Kwang Hong
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    ABSTRACT: A formula diet based on pork meat oligopeptides(pork meat protein hydrolysates) was designed for experimental hepatitic rats. The rats were given D-galactosamine for 6 days. During this period, the rats were provided with a 12% casein diet or the formula diet which was low in aromatic amino acids and rich in branched chain amino acids. The formula diet was prepared using pork meat oligopeptides as the principal nitrogen source. The hepatitic rats given the formula diet had lower plasma GOT and GPT concentrations. Additionally, the fischer ratio of the plasma was significantly lower in those rats. However, there was no significant difference in the plasma insulin-like growth factor-I concentration before and after acid-ethanol extraction among groups. These results suggest that the formula diet was better for the animals than the casein diet. Furthermore, these findings suggest that pork meat oligopeptides are an excellent material for preparation of formula diets for patients suffering from hepatitis.
    The Korean Journal of Food And Nutrition. 01/2009; 22(3).
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    ABSTRACT: The sgtR1 and sgtR2 genes encoding putative regulators similar to the Aha1 and ArsR families, respectively, were identified downstream from the sprT gene. To investigate their function, expression vectors containing various combinations of sprT, sgtR1, and sgtR2 were transformed into Streptomyces lividans and Streptomyces griseus. The trypsin activity levels produced by S. lividans harboring pWHM3-TR2 (sprT and sgtR2) or pWHM3-TR1R2 (sprT, sgtR2, and sgtR2) were, respectively, 6.6 or 8.9 times that of S. lividans transformed with pWHM3-T (sprT). In the pWHM3-TR1R2 transformant, the transcription of sprT consistently occurred during the earlier stages of growth and was maintained at a higher level throughout the 6 days of cultivation. Streptomyces griseus IFO13350 harboring pWHM3-TR1R2 also produced trypsin activity 2.1 times that of the pWHM3-T transformant. However, all S. griseus Delta adpA transformants produced lower SGT activity than the wild-type strain, and none could overcome the deficiency in AdpA transcriptional activator, suggesting that AdpA is an absolute prerequisite for sprT expression. The sprT transcript was detected at a high level only in the wild-type strain, but the sgtR1 and sgtR2 transcript levels were very similar between the S. griseus IFO13350 and Delta adpA strains. This clearly demonstrates that the transcription of the sgtR1 and sgtR2 genes is not dependent on AdpA and that they are therefore not members of the AdpA regulon.
    FEMS Microbiology Letters 12/2007; 276(1):75-82. · 2.05 Impact Factor
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    ABSTRACT: The sprC gene encodes Streptomyces griseus protease C (SGPC), a bacterial chymotrypsin-like serine protease. Because the published data on sprC was not complete, we cloned and analyzed a new DNA fragment spanning downstream to upstream of the sprC gene from S. griseus IFO13350. The cloned 2.3-kb DNA fragment was placed on a high-copy number plasmid and introduced into Streptomyces lividans TK24. Chymotrypsin activity of the transformant was 8.5 times higher than that of the control after 3 days of cultivation and stably maintained until 9 days of cultivation, which clearly indicated that the cloned 2.3-kb fragment contained the entire sprC gene with its own promoter. When the same construct was introduced in the S. griseus IFO13350 (wild strain) and its two mutant strains in the A-factor regulatory cascade, deltaadpA and HO1, the chymotrypsin activity increased fivefold only in the deltaadpA strain. Transcriptional analysis based on RT-PCR revealed that the sprC gene is normally transcribed in both strains; however, earlier transcription was observed in the wild strain compared with the deltaadpA strain. A gel mobility shift assay showed that the AdpA protein did not bind to the promoter region of sprC. All these data clearly indicate that the expression of sprC is not dependent on the AdpA protein, but is distinctly regulated from other chymotrypsin genes composing an AdpA regulon. Earlier morphological differentiation was observed in S. lividans TK24, and S. griseus IFO13350 and HO1, transformed with the expression vector. The transformant of S. griseus deltaadpA formed markedly larger colonies. Antisense repression of sprC resulted in severe decrease of chymotrypsin activity, down to one-third of the control, and delayed morphological differentiation. All these data suggest that SGPC is related to normal morphogenesis in S. griseus.
    Journal of Microbiology and Biotechnology 02/2007; 17(1):81-8. · 1.40 Impact Factor
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    ABSTRACT: Gelatinase is a proteolytic enzyme that hydrolyzes gelatin. Gelatinolytic activity was detected from cul-ture broths of Streptomyces griseus IFO13350 and HH1 by paper disc assays on 0.5% agar plates con-taining 1% gelatin. The concentrated extracellular protein from the S. griseus was analyzed by SDS polyacrylamide gel, and two proteins, with molecular weights of 30 and 28 kDa, respectively, were iden-tified to have gelatinase activity by gelatin zymography. The protein with a molecular weight of 28 kDa was confirmed to be S. griseus trypsin (SGT). The effects of metal ions and metal chelators on the pro-tease activity of the SGT were studied. Of the metal ions tested, only manganese was found to enhance the protease activity, 2.6 times, however, Co 2+ , Cu 2+ , and Zn 2+ , and metal chelators, such as EDTA and EGTA, inhibited the SGT activity. When the protease activity of the SGT was measured at various pHs, in the presence of 5 mM MnCl 2 , its highest activity was at pH 11.0, whereas only 60% of the maximum activity was observed between pHs 4.0 and pH 6.0, and almost 80% activity between pHs 7.0 to pH 10.0. The protease activity was measured at various temperatures in the presence of 5 mM MnCl 2 . The SGT was found to be stable up to 60 o C for 30 min, while only 16% of the enzyme activity remained at 60 o C, and at 80 o C almost all the activity was lost. The optimal temperature for the protease activity was 50 o C. The genus Streptomyces is comprised of gram-positive soil bacteria with a complex life cycle. In addition to the com-plex morphological differentiation, Streptomyces are able to produce many kinds of secondary metabolites, including antibiotics and biologically active substances. Streptomyces griseus is a representative strain, and has been extensively studied for its regulatory cascade concerning streptomycin production and morphological differentiation (Uhnmee et al., 1998). A-factor (2-isocapryloyl-3-γ-hydroxy-methyl-butyrolactone) is a microbial hormone that plays a role as a positive regulator for the productions of streptomycin and sporulation in S. griseus (Vujaklija et al., 1991). The reg-ulatory network in the cell, starting from A-factor, has almost elucidated (Horinouchi, 2002). According to our results, certain proteases are produced in different manners in S. griseus strains IFO13350 and HH1, the later being an A-factor deficient strain. In addi-tion, some serine protease and metalloprotease inhibitors induce the retardation of spore formation. With regard to these data, it has been suggested that certain proteases may be involved in the Streptomyces differentiation pro-cesses (Kim et al., 2000). S. griseus produces, not only a mixture of proteases, sold under the commercial name of Pronase, but also many kinds of secondary metabolites (Awad et al., 1972). Many genes, such as sprA, sprB, sprC, sprD, sprE, and sprT, that encode S. griseus protease A (SGPA), S. griseus protease B (SGPB), S. griseus protease C (SGPC), S. gri-seus protease D (SGPD), and S. griseus protease E (SGPE), and S. griseus trypsin (SGT), respectively, have also been cloned and analyzed (Olfason et al., 1975; Kim et al., 1991). All the proteases reported from S. griseus belong to the bacterial serine proteases that catalyze the hydrolysis of amides and esters, through a common cat-alytic mechanism, and involve a triad of the residues serine, histidine and aspartic acid (Narahashi et al., 1968; Trop et al., 1970; Lee et al., 2000). SGT is a bacterial serine protease with greater similarity to a mammalian protease than to either S. griseus pro-teases A and B (Trop et al., 1968; Nishikata et al., 1981).
    The Journal of Microbiology. 01/2004; 41:289-294.