• BMB Reports
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• 제32권1호
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• pp.12-19
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• 1999

Gaegurin 4 (GGN4), a broad-spectrum antibiotic, is a 37-amino acid peptide isolated from the Korean frog, Rana rugosa. In this study, we have chemically synthesized and purified GGN4 analogues where the C-terminal portion is truncated and/or substituted with tryptophan. These peptides show significantly different biological activities depending on the location of tryptophan and the number of amino acids truncated from the C-terminal end. While deletion of 9 amino acids from the C-terminal seems to be marginally tolerable in maintaining the antimicrobial activity, further deletion of up to 14 amino acid residues decreases the potency by more than 60-fold towards Gram-positive, and 10-fold towards Gram-negative, bacteria. Surprisingly, the reduced activity of the shorter peptide can be completely restored by a single substitution of aspartic acid 16 to tryptophan 16 (D16W). Also, the truncation seems to decrease the specificity of antibiotic activity more towards Gram-positive than towards Gram-negative bacteria studied. These data suggest a partial role of the C-terminal region in determining the binding specificity and the activity of peptides upon binding to their target cell membranes.

• 한국식품영양학회지
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• 제7권1호
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• pp.1-7
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• 1994

To investigate the characteristics of active sites of the D-xylanase and $\beta$-xylosidase purified from Penicillium verruculosum, effects of various chemicals on the enzyme activity were analyzed. The D-xylanase was activated by Cua), however it was inhibited by metal ions, Hg2+ and Mna+, by chemicals, N-bromosuccinimide, iodine, diethylpyrocarbonate, and 2,3-butanedione. These results suggested that the D-xylanase from Penicillium verruculosum contained tyrosine, histidine, arginine and tryptophan at the active center. The $\beta$-xylosidase was inhibited by Hg2+, N-bromosuccinimide and sodium dodecyl sulfate, however it was not effected by Mn2+ and Cu2). It was suggested that the enzyme contained tryptophan at the active center.

• Korean Membrane Journal
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• 제5권1호
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• pp.25-30
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• 2003

Chitosan membranes crosslinked with glutaraldehayde that contained chiral environment were prepared. The chitosan membranes were characterized using FTIR and swelling index measurements. Their swelling index in water ranged from 100 to 70%, depending on the crosslinking time. The separation of D- and L-isomers of tryptophan was achieved through a pressure driven membrane separation process, using the self-supporting crosslinked chitosan membranes. The chiral separation performance of the membranes depended strongly on the swelling index of the membranes and the separation conditions such as concentration of feed solutions and different operating pressures. Especially when a chitosan membrane with a swelling index of 70% was used, almost complete optical resolution of D- and L-tryptophan was obtained ; enantiomeric excess (ee %) of 97.92% and flux of 2.26 g/㎡$.$h.

• 미생물학회지
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• 제28권2호
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• pp.174-179
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• 1990

L-Phenylalanine을 대량생산하는 균주를 얻기 위하여 Escherichia coli K-12로부터 여러대사조절 변이주를 분리하였다. MWEC 83은 L-phenylalanine을 7.4 g/l 생산하는 tyrosine, tryptophan 이중 영양요구성 변이주이다. Tyrosine과 tryptop phan의 첨가없이 L-phenylalanine을 생산하기 위하여 MWEC 83으로부터 복기변이주 MWEC 101을 분리하였다. 또한 MWEC 101 균주로부터 여러 analog와 valine 내성주를 분리하였다. MWEC 101-5는 포도당 15%로 배양 54시간에 17.9 g/l의 L-phenylalanine을 생산하는 최고 우량균주이다. MWEC 101-5의 chorismate mutase와 prephenate dehydratase 효소환성은, 효소반응 혼합액 속에 2mM phenylalanine에 대하여 효소활성이 저해되지 않았다.

• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.43-50
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• 1998

Three hundred and fifty-two growing pigs were utilized in three growth trials to investigate the effects of crystalline amino acid supplementation on growing pigs' growth performance and feed consumption. In Exp. 1, diets were formulated on the basis of digestible amino acids. Utilization of rapeseed meal plus cottonseed meal (R + C) in diet supported similar average daily gain (ADG), feed/gain (F/G) and cost per gain (p > 0.05) to group of soybean meal (SBM). In Exp. 2, 14% CP diets containing equal amount of cottonseed meal and rapeseed meal were formulated with the addition of threonine and/or tryptophan. Supplementation with threonine improved ADG and F/G (p < 0.05). Supplementation with only tryptophan made no benefits for ADG of growing pigs. In Exp. 3, diets with different threonine level were formulated. Increasing dietary threonine to 0.54% improved (p < 0.05) ADG and F/G compared to 0.45% dietary threonine. Increase in dietary threonine did not improve ADG (p > 0.05) but decreased F/G (p < 0.05) because of a decrease in average daily feed intake. Pigs fed diet with dietary threonine/lysine ratio of 67.5% supported optimum growth performance.

• 멤브레인
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• 제16권2호
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• pp.133-143
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• 2006

방사선 그라프트 중합법을 적용하여, 폴리에틸렌 다공성 중공사막에 전자선을 조사시킨 후, glycidyl methacrylate(GMA)를 그라프트 중합하였다. 그 후, 음이온 교환기로서 diethylamine (DEA), triethylamine (TEA)를 도입시켜 2종류의 음이온 교환막을 합성하였다. DEA막과 TEA막의 이온교환 밀도는 3.4 mmol/g, 1.74 mmol/g으로 DEA막이 TEA막보다 높은 이온교환기를 얻을 수 있었다. 이 2종류의 음이온교환막에 단백질(bovine serum albumin, BSA)을 투과법에 의해 고정시켜 BSA 고정막을 만들었다. DEA-BSA막의 경우, 그라프트 체인에 BSA가 8층 이상으로 다층 흡착하였으나, TEA-BSA막의 경우, 강한 음이온에 의해 다층 흡착이 이루어지지 않았다. DEA-BSA막의 경우, BSA 다층 흡착성 고정을 나타내기 때문에 L-Trp가 D-Trp보다 더 강한 흡착 특성을 나타내었다. L, D-Trp 이성질체 혼합물을 투과시킨 BTC에 있어서, DEA-BSA 막의 경우, BSA에 대한 L-Trp와 D-Trp의 키랄 인식이 다르기 때문에 2단계의 BTC곡선을 얻을 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.969-977
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• 2024

Indigo is a valuable, natural blue dye that has been used for centuries in the textile industry. The large-scale commercial production of indigo relies on its extraction from plants and chemical synthesis. Studies are being conducted to develop methods for environment-friendly and sustainable production of indigo using genetically engineered microbes. Here, to enhance the yield of bioindigo from an E. coli whole-cell system containing tryptophanase (TnaA) and flavin-containing monooxygenase (FMO), we evaluated tryptophan transporters to improve the transport of aromatic compounds, such as indole and tryptophan, which are not easily soluble and passable through cell walls. Among the three transporters, Mtr, AroP, and TnaB, AroP enhanced indigo production the most. The combination of each transporter with AroP was also evaluated, and the combination of AroP and TnaB showed the best performance compared to the single transporters and two transporters. Bioindigo production was then optimized by examining the culture medium, temperature, isopropyl β-D-1-thiogalactopyranoside concentration, shaking speed (rpm), and pH. The novel strain containing aroP and tnaB plasmid with tnaA and FMO produced 8.77 mM (2.3 g/l) of bioindigo after 66 h of culture. The produced bioindigo was further recovered using a simple method and used as a watercolor dye, showing good mixing with other colors and color retention for a relatively long time. This study presents an effective strategy for enhancing indigo production using a combination of transporters.

• 생명과학회지
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• 제14권1호
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• pp.17-20
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• 2004

대장균 트립토판 합성효소의 $\beta$반응의 빠른 속도 반응에 일가 양이온의 영향을 D56N과 D56G 잔기치환체를 대상으로 조사하였다. 일가 양이온을 처리하였을 때 생성되는 중간반응 생성물의 생성과 분해 속도가 영향을 받았다. 56번 자리 잔기치환체도 야생형에 비해 반응의 중간산물의 생성과 분해에 있어 모두 느린 속도를 보여주고 있다. 이들 잔기 치환체에 미치는 일가 양이온의 영향 또한 달라졌다. 이 결과는 대장균의 효소에서도 56번잔기가 이소조절에 관여하고 있고, 이 과정에서 일가 양이온들이 이소조절 리간드역할을 수행하는 것을 보여준다.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.68-72
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• 1992

Aeromonas, salmonicida YA7-625가 생산하는 chitinase는 $Hg^{2+}$에 의해 저해를 받았으나, $\beta$-mercaptoethanol 처리에 의해서 활성이 보호되었으며 Na-thiosulfate, ascorbic acid등의 환원제들과 sodium azide, p-CMB 등의 -SH 저해제에대하여 전혀 작용을 받지 않았으므로 본 효소의 활성중심에는 -SH가 없는 것으로 생각되었다. 또한 histidine, cysteine, tyrosine 및 trytophan에 작용하는 iodine에 의하여 저해를 받았으며 tryptophan에 대해 특이적으로 작용하는 N-bromosuccinimide에 의해 실활되는 것으로 보아 활성중심에 tryptophan, histidine 및 tyrosine 가 존재하는 것으로 생각되었다.

• 한국가시화정보학회지
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• 제11권2호
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• pp.41-45
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• 2013

Two-photon microscopy (TPM) is minimally-invasive 3D fluorescence microscopy based on nonlinear excitation, and TPM can visualize cellular structures based on auto-fluorescence. Line-scanning TPM is one of high-speed TPM methods without sacrificing the image resolution by using spatial and temporal focusing. In this paper, we developed line-scanning TPM based on spatial and temporal focusing for auto-fluorescence imaging by exciting the tryptophan. Laser source for this system was an optical parametric oscillator (OPO) and it made near 570 nm femtosecond pulse laser. It had 200fs pulse width and 1.72 nm bandwidth, so that the achievable depth resolution was 2.41um and field of view (FOV) is 10.8um. From the characterization, our system has 3.0 um depth resolution and 12.3 um FOV. We visualized fixed leukocyte cell sample and compared with point scanning system.