• 한국응용과학기술학회지
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• 제32권4호
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• pp.758-766
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• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• 대한수의학회지
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• 제29권1호
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• pp.13-20
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• 1989

The proteins of the bovine erythrocyte membrane were analyzed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and their relations to the slow sedimentation rate of bovine erythrocytes were investigated by treating the erythrocytes with trypsin. The erythrocyte sedimentation rates of bovine erythrocytes from Holstein and Korean native cattle were very slow compared with the human one (1/7 as slow as the human one) as reported previously. However, when human and Holstein erythrocytes were treated with trypsin (0.2 and 0.5 mg/ml) for 1 hour at ${37^{\circ}C}$, their sedimentation rates were markedly accelerated while the sedimentation rate of Korean native cattle's erythrocytes were not affected. Although the general protein profiles of the bovine erythrocyte membranes were almost similar to that of human, bovine erythrocyte membranes showed one additional protein band, called band Q in this study, which migrated electrophoretically to the mid-position between band 2 and band 3 in human erythrocyte membranes. Treatment of Holstein and human erythrocytes with trypsin caused a decrease or disapperance of the band Q from the erythrocyte membrane. Although the band Q in Korean native cattle's erythroyte membrane was decreased by trypsin treatment of the erythrocytes, the magnitude of the decrement was not so pronounced as in the case of human and Holstein erythrocytes. The glycoprotein profiles of the bovine erythrocyte membranes revealed by periodic acid-Schiff stain showed a marked difference from that of human. The PAS-1 (glycophorin) and PAS-2 (sialoglycoprotein) present in human erythrocyte membrane were almost absent from the bovine erythrocyte membranes. Instead, the bovine erythrocyte membranes showed a strong PAS-positive band near the origin of the electrophorograms, which is named as PAS-B in this study. The PAS-B band was disappered completely by the trypsin treatment of Holstein erythrocytes whereas the PAS-B band in Korean native cattle's erythrocyte membrane still remained after the trypsin treatment. The trypsin treatment of Korean native cattle's erythrocytes, however, led to the appearance of small molecular weight peptides, indicating that the high molecular weight glycoproteins were degraded by trypsin as in human and Holstein ones. These results suggest that the slow sedimentation rate of bovine erythrocytes is due in part to the presence of band Q protein fraction and PAS-B glycoprotein in the bovine erythrocytes.

• Molecules and Cells
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• 제39권8호
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• pp.594-602
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• 2016

Alkyl hydroperoxide reductase subunit C from Pseudomonas aeruginosa PAO1 (PaAhpC) is a member of the 2-Cys peroxiredoxin family. Here, we examined the peroxidase and molecular chaperone functions of PaAhpC using a site-directed mutagenesis approach by substitution of Ser and Thr residues with Cys at positions 78 and 105 located between two catalytic cysteines. Substitution of Ser with Cys at position 78 enhanced the chaperone activity of the mutant (S78C-PaAhpC) by approximately 9-fold compared with that of the wild-type protein (WT-PaAhpC). This increased activity may have been associated with the proportionate increase in the high-molecular-weight (HMW) fraction and enhanced hydrophobicity of S78C-PaAhpC. Homology modeling revealed that mutation of $Ser^{78}$ to $Cys^{78}$ resulted in a more compact decameric structure than that observed in WT-PaAhpC and decreased the atomic distance between the two neighboring sulfur atoms of $Cys^{78}$ in the dimer-dimer interface of S78C-PaAhpC, which could be responsible for the enhanced hydrophobic interaction at the dimer-dimer interface. Furthermore, complementation assays showed that S78C-PaAhpC exhibited greatly improved the heat tolerance, resulting in enhanced1 survival under thermal stress. Thus, addition of Cys at position 78 in PaAhpC modulated the functional shifting of this protein from a peroxidase to a chaperone.

• 한국균학회지
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• 제23권2호통권73호
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• pp.121-128
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• 1995

Agrocybe cylindracea의 톱밥배양 균사체로부터 항암효과가 있는 것으로 알려진 단백다당류를 분리, 정제하였으며 그 특성을 조사하였다. Agrocybe cylindracea 균사체로부터 열수추출한 조단백다당류(Fr.CB)의 수율은 ethanol 농도가 95%일 때 2.974 g으로서 원재료인 톱밥균사체를 기준으로 0.74%였다. 이 조단백다당류(Fr.CB)를 박막여과, ion exchange chromatography, 그리고 gel filtration에 의해 정제하였다. 조단백다당류 Fr.CB를 박막여과하여 분획한 결과 분자량 30만 이상의 분획(Fr.B)이 38.6%를 차지하여 고분자 단백다당류가 주성분임을 알 수 있었다. Fr.B를 ion exchange chromatography로 분리한 결과 2개의 분획이 17.4%(Fr.B-1), 10.3%(Fr.B-2)의 수율로 얻어졌다. 이들 분획을 농축한 다음 gel filtration한 결과 거의 순수한 단일 단백다당류의 peak를 얻을 수 있었다. Fr.B-1을 분리하여 얻은 $Fr.B-1-{\beta}$ 분획의 수율은 Fr.B-1을 기준으로 42.5%였다. 항암효과의 가능성이 가장 높은 것으로 판단되는 최종 정제된 분획인 $Fr.B-1-{\beta}$의 분자량은 710 KDa 부근이었으며 단당류의 조성을 HPLC로 분석한 결과, glucose가 주성분이었고 그외 fucose, galactose도 검출되었다. 또한 아미노산 조성을 분석한 결과 glutamic acid, alanine이 비교적 많이 검출되었고 cysteine은 검출되지 않았다.

• 한국연소학회지
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• 제7권4호
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• pp.36-44
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• 2002

Carbon molecules with closed-cage structures are called fullerenes $(C_{60},\;C_{70})$, whose applications include super-conductors, sensors, catalysts, optical and electronic device, polymer composites, and biological and medical materials. The synthesis of fullerenes has been recently studied with low-pressure benzene/argon/oxygen flames. The formation of fullerene is known as molecular weight growth processes of PAHs (polycyclic aromatic hydrocarbon). This study presents results of PAHs and fullerene measurements performed in a low-pressure benzene/argon/oxygen normal co-flow laminar diffusion flame. Through the central tube of the burner, benzene vapors carried by argon are injected. The benzene vapors are made in a temperature-controlled bubbler. The burner is located in a chamber, equipped with a sampling system for direct collection of condensable species from the flame, and exhausted to a vacuum pump. Samples of the condensable are analyzed by HPLC (High Performance Liquid Chromatography) to determine the yields of PAHs and fullerene. Also, we computed mole fraction of fullerene and PAHs in a nearly sooting low pressure premixed, one-dimensional benzene/argon/oxygen flame (equivalence ratio ${\Phi}=2.4$, pressure=5.33kPa). The object of computation was to investigate the formation mechanism of fullerenes and PAHs. The computations were performed with CHEMKIN/PREMIX. As a result of this study, fullerenes were synthesized in a low pressure (20torr) $C_6H_6/Ar/O_2$ flames and the highest concentration of fullerene was detected just above the visible surface of a flame.

• Applied Biological Chemistry
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• 제31권4호
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• pp.331-338
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• 1988

칡뿌리로 부터 칡뿌리 acetone분말을 제조하고 polyphenol oxidase를 추출, 정제하여 정제효소의 효소학적 특성을 검토하였다. 조효소는 DEAE-Cellulose, DEAE-Sephadex A-50, Sephadex G-100 column chromatography에 의하여 정제되었으며, 정제효소의 비활성은 94배, 정제수율은 45.4%이었다. 정제효소는 catechol 및 pyrogallol에 대하여 감한 친화성을 나타내었으며, km 값은 catechel을 기질로 하였을 때 16.67mM이었다. 작용 최적 pH는 7.5, 최적온도는 $50^{\circ}C$에서 가장 잘 작용하였고 1mM L-ascorbic acid, sodium bisulfite, EDTA, KCN 및 $Fe^{3+}$ 이온에 의하여 심한 저해를 나타내었으며, $Zn^{2+}$ 이온을 약 1.7배 정도의 활성을 증가시켰다. 조효소액을 전기영동하여 catechol로 활성염색 하였을 때 5개 isoenzyme이 확인되었으며 그 중 분자량 35,000의 것이 가장 강한 활성을 나타내었다.

• 한국식품영양과학회지
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• 제44권11호
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• pp.1645-1652
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• 2015

해양생물 유래 피부건강 기능성의 소재를 발굴할 목적으로 굴 단백질을 Protamex와 Neutrase로 가수분해 한 후 생성된 굴 가수분해물 펩타이드의 주름 개선 효과를 조사하였다. 굴 가수분해물은 약 7.9%의 유리아미노산을 포함하며 urea, taurine, alanine, glycine 등의 아미노산의 함량이 높았다. 굴 가수분해물은 collagenase 저해 활성을 가지고 있었고, 피부세포인 CCD986sk에 대한 독성은 없었다. 분획물의 수율은 1,000 Da 미만이 40%였으며, 5,000 Da 미만이 60.4%를 차지하였다. 1,000~3,000 Da인 분획물이 항산화 활성, procollagen의 생성능 및 MMP-1 효소 저해 활성이 가장 높았다. 굴 가수분해물과 5,000 Da 미만의 분획물은 주름 개선을 위한 피부건강 기능성 소재로서 화장품 등의 제품에 응용 가능함을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.922-928
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• 1997

The conformational transition of poly(L-proline) (PLP), Form Ⅱ → Form Ⅰ and the intermolecular aggregation of the product, Form Ⅰ, during and after the transition in water-propanol (1:7, 1:9, 1:15.7, and 1:29 v/v) were studied. For the study, the viscosity change and excess light scattering intensity were measured in the course of the transition which was determined by the Form Ⅰ fraction, fI of the sample solution. For the PLP sample of molecular weight Mv=31,000 the experimental results show that the reaction course is roughly divided into three regions: in the first region [fI=0.27 to 0.40 (- [α]D=400 to 330)], the conformational change of Form Ⅱ → Form Ⅰ occurs with decrease of viscosity, in the second region [fI=0.40 to 0.80 (- [α]D=330 to 120)], a partial side-by-side (p-S-S) type aggregation in which Form Ⅰ blocks interact with each other, which induces the increase of viscosity, starts to occur, and in the third region [fI=0.80 to 1.00 (- [α]D=120 to 15)], a side-by-side type (raft like) aggregation of Form Ⅰ or an end-to-end (E-E) type aggregation occurs according to the solvent situation, i.e., in a water-rich medium [water-propanol (1:9 or 1:7 v/v)], the (S-S) type aggregation with a gross decrease in viscosity occurs while in a water-poor medium [water-propanol (1:29 or 1:15.7 v/v), the (E-E) type aggregation with a large increase in viscosity occurs. The (S-S) type aggregation was promoted at high temperatures. Based on the structure of PLP, a reasonable mechanism for the (p-S-S) and (S-S) aggregation which occurs with the transition of Form Ⅱ → Form Ⅰ is considered. The suggested mechanism was also supported by the result of chain length effect of PLP for the aggregation.

• 한국식품과학회지
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• 제36권3호
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• pp.484-489
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• 2004

인간의 장내 상재 세균이며 인간에게 다양한 건강 증진 효과를 부여하는 것으로 알려진 Bifidobacterium속을 유아의 분변으로부터 분리하여 세포질, 세포벽 및 배양액의 고분자 획분을 대상으로 in vitro에서 장관면역계를 경유한 골수세포 증식활성을 검토하였다 분리한 6종의 Bifidobacterium속 중에서 Bifidobacterium SL-21의 세포벽 성분(CWP)이 농도 의존적으로 가장 높은 골수세포의 증식을 나타내었다. 한편, 골수세포 증식은 Peyer's patch를 매개로 일어나는 반응이므로 Peyer's patch에 의해 생성되는 cytokine류의 활성을 측정하였다. B. bifidum SL-21의 세포벽 성분과의 반응에 의해 GM-CSF, IL-2 및 IL-6 등의 cytokine류의 생산 증가가 확인되었으며 cytokine의 생산은 반응한 세포벽 성분에 농도 의존적 경향을 보였고 골수세포 증식이 증가할수록 높은 cytokine 생산 증가를 나타냈다. 불용성인 B. bifidum SL-21 세포벽을 lysozyme 처리하여 수용화시켜 분자량에 따른 활성을 검토한 결과, 분자량 30-50 kDa의 획분에서 가장 높은 골수세포 증식활성이 측정되었다. 이와 같은 결과를 토대로 하여 B. bifidum SL-21 세포벽 성분이 Peyer's patch의 림프구를 활성화시키고 이들 활성화된 림프구에서 생성되는 cytokine류에 의해 골수세포 증식이 이루어짐을 확인할 수 있었다. 또한 이들 활성화된 면역세포는 CM-CSF, IL-2 및 IL-6 등의 전신순환 면역계의 증강에 중요한 역할을 갖는 cytokine류를 생산하였다.

• 생명과학회지
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• 제17권10호
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• pp.1321-1329
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• 2007

사슴뿔은 동물세계에서 가장 빨리 성장하는 조직이다. 따라서 성장중인 사슴뿔은 뼈 성장을 촉진하는 인자가 풍부하게 포함된 것으로 생각된다. 이들 성장인자들 중 IGF-1은 뼈를 자라게 하는 조골세포의 대사에 중요한 역할을 한다고 알려져 있어 이를 정제하고자 하였다. IGF-1의 정제는 상대라고 불리는 신선한 사슴뿔을 유안침전, DEAE-Sepharose CL-6B 이온교환수지, CM-Sepharose CL-6B 양이온교환수지, Sephadex G-50의 순차적인 방법으로 할 수 있었다. 각 과정마다 IGF-1의 거동을 HPLC, SDS-PAGE, Dot blot, 그리고 western blot으로 분석하였다. IGF-1의 정량은 ELISA기술로 재조합 인간 IGF-1을 이용하여 계산되었으며, 최종 분별 액은 두 개의 단백질을 보였으나, Western-blot에서 작은 분자량인 12 kDa으로 최종 판명할 수 있었다. 정제된 단백질은 HPLC에서 retention 시간 8분만에 검출되었으며, 총 농도는 2910 ng/ml 이고 중량은 0.291 g 이었다.