• Korean Chemical Engineering Research
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• 제49권4호
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• pp.475-479
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• 2011

키토산은 천연고분자 물질로 다양한 물리화학적(다중양이온, 반응성 수산화기와 아미노기 그룹), 생물학적(생리활성, 생체적합성, 생분해성) 특성을 가지고 있다. 본 연구에서는 겔형성제로 폴리감마글루탐산을 이용하여 키토산 나노입자를 제조하였다. 나노입자는 폴리감마글루탐산의 카르복실기($-COO^-$)와 키토산의 아미노기($-NH_3^+$)사이의 이온 상호작용에 의해 형성되었다. 키토산(0.1~1 g)을 100 ml 아세트산 용액(1% v/v)에 첨가한 후 상온에서 충분히 용해되도록 하룻밤 동안 교반하였다. 폴리감마글루탐산(0.1 g)은 상온에서 90 ml 증류수에 용해시켰다. 교반되고 있는 폴리감마글루탐산 용액에 키토산 용액을 주사바늘을 통해 상온에서 적가하였다. 입자의 평균 크기는 80~300 nm 범위에서 형성되었다. 키토산/폴리감마글루탐산 나노입자는 중금속 이온들($Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$, $Ni^{2+}$)의 제거를 위해 콜로이드 상태의 흡착 물질로 사용되었다. 나노입자의 중금속 제거 능력은 $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Ni^{2+}$ > $Zn^{2+}$의 결과를 보였다.

• 농업과학연구
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• 제34권2호
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• pp.161-170
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• 2007

Poly($\gamma$-glutamic acid) 및 levan의 생성균주로 알려진 Bacillus subtilis BS 62의 $\gamma$-GTP(ggt) 유전자를 해석하기 위하여 PCR 반응에 의해 BS 62의 염색체 DNA로부터 약 2.5 kb의 $\gamma$-GTP(ggt) 유전자 분획을 얻어 그 PCR 산물의 염기서열을 분석하여 기왕에 보고된 기타의 ggt 유전자와 비교 분석한 결과, B. subtilis $\gamma$-GTP 유전자(BSU49358)와 98%의 높은 상동성을 보였으며, Pseudomonas sp. A14(S63255)와는 37%, 방선균인 Streptomyces avermitils(AP005028)의 게놈 DNA와는 38%의 상동성을 나타냈다. BS 62의 $\gamma$-GTP 유전자의 open reading frame은 587개의 amino acid로 구성된 polypeptide의 것으로 해석되었으며, N-terminal의 28개 아미노산은 B. subtilis 펩타이드의 전형적인 형태를 보였고, 전형적인 리보솜의 부착부위는 개시코돈 ATG의 위쪽 7번에서 12번 염기(AGGAGG)에 위치하였고, 그리고 종지코돈 다음에서는 stem-loop 구조, ORF의 위쪽 약 50 bp 지점에서는 catabolite-responsive element가 발견되었다. 또한 B. subtilis 효소의 촉매자리로 추정되는 467번 잔기는 threonine으로서, 다른 박테리아의 serine, 포유동물의 cysteine과는 구별되는 것이었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.246.2-247
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• 2002

In this study. we tried to investigate whether polymerized basic amino acid e.g. poly-L-lysine(PLL) which has the molecular weight under 10 kD significantly affects the physiological and stimulated mucin release from cultured hamster tracheal surface epithelial cells. Confluent primary hamster tracheal surface epithelial(HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 hr and chased for 30 min in the presence of either PLLs or adenosine triphosphate(ATP) and PLL to assess the effects on basic or ATP-stimulated 3H-mucin release. (omitted)

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.352-352
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• 2006

Corynebacterium glutamicum, which is well known as an amino acid fermentation bacterium, has been used as a producer of poly(3-hydroxybutyrate) [P(3HB)]. P(3HB) was synthesized in recombinant C. glutamicum harboring the expression plasmid vector with a strong promoter for cell surface protein gene derived from C. glutamicum and P(3HB) biosynthetic gene operon derived from Ralstonia eutropha. The expression of P(3HB) synthase gene was detected by enzyme activity assay. Intracellular P(3HB) was microscopically observed as inclusion granules and its content was calculated to be 22.5 % (w/w) with molecular weight of $2.1{\times}10^{5}$ and polydispersity of 1.63.

• International Journal of Industrial Entomology and Biomaterials
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• 제20권1호
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• pp.25-28
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• 2010

Silk fibroin was conjugated with methoxypoly(ethylene glycol) derivatives to prepare silk nanoparicles. Conjugation of SF with PEG was examined with various instrumental analyses. Nuclear magnetic resonance spectrometry and amino acid analysis showed that serine and tyrosine residues in SF were reacted with PEG and resulted in increasing molecular weight. The sizes and shapes of SF nanoparticles observed by transmission electronmicroscope were ranged about 150-400 nm in diameter and spherical morphology. UV/VIS spectrometry showed SF nanoparticles might be outer PEG and inner SF structure.

• BMB Reports
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• 제45권1호
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• pp.14-19
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• 2012

A feruloyl esterase encoding gene (designated fae6), derived from a leachate metagenomic library, was cloned and the nucleotide sequence of the insert DNA determined. Translational analysis revealed that fae6 consists of a 515 amino acid poly-peptide, encoding a 55 kDa pre-protein. The Fae6 primary structure contained the G-E-S-A-G sequence, which corresponds well with a typical catalytic serine sequence motif (G-x-S-x-G). The fae6 gene was successfully over-expressed in E. coli and the recombinant protein was purified to 8.4 fold enrichment with 17% recovery. The $K_M$ data showed Fae6 has a high affinity to methyl sinapate while thermostability data indicated that fae6 was thermolabile with a half life ($T_{1/2}$) < 30 min at $50^{\circ}C$. High affinity for Fae6 against methyl sinapate, methyl ferulate and ethyl ferulate suggest that the enzyme can be useful in hydrolyzing ferulated polysaccharides in a biorefinery process.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.193-196
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• 2004

The peptide Arg-Gly-Asp (RGD) was immobilized through their amino terminus to ends of a sugar bearing copolymer, producing a functional hybrid copolymer. Poly(N-p-vinylbenzyl-D-maltonamide-co-6-(p-vinylbenzamido)-hexanoic acid-g-GRGDS) [p(VMA-co-VBGRGDS)] promoted the attachment and growth of NIH fibroblast cells. The interaction between fibroblast cells and p(VMA-co- VBGRGDS) copolymer resulted in effective cell attachment, proliferation, and morphological changes by introduction of a GRGDS sequence. Moreover, when pretreated with soluble RGD monomer, attachment of fibroblast cells was suppressed approximately 50% from that of the p(VMA-co-VBGRGDS) surface.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.529-529
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• 2012

Dispersion of carbon nanotubes in biocompatible media are of particular interest for diverse biomedical and nanomedicine applications. Various biomolecules and biopolymers such as DNA, proteins, poly L-lysine, starch, gelatin, steroid biosurfactants, and chitosan have shown capability for the effective dispersion of carbon nanotubes in water. Chitosan has demonstrated capacity for effective dispersion of single-walled carbon nanotubes (SWCNTs) in acidic medium and it also showed tendency to preferentially disperse smaller diameter nanotubes. Chemical functionalizations of chitosan enable its solubility in neutral pH water by reducing the intra and inter molecular hydrogen bonding. Herein, we present a neutral pH water soluble chitosan derivative, chitosan-hydroxyphenyl acetamide (CHPA), obtained by functionalizing the amino groups of chitosan with 4-hydroxyphenyl acetic acid, as an efficient biocompatible dispersant for debundling and solubilization of SWNTs in neutral aqueous solutions. Various process conditions for individual dispersion of SWCNTs are analyzed based on optical absorption and Raman spectroscopy.

• Journal of Microbiology and Biotechnology
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• 제7권4호
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• pp.229-236
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• 1997

A gene, $phbC_{2.4.1}$ encoding poly-3-hydroxybutyric acid (PHB) synthase of Rhodobacter sphaeroides 2.4.1 was cloned by employing heterologous expression in Escherichia coli. R. sphaeroides chromosomal DNA partially digested with MboI was cloned in pUC19 followed by mobilization into E. coli harbouring $phbA,B_{AC}$ in pRK415, which code for ${\beta}$-ketothiolase and acetoacetyl CoA reductase of Alcaligenes eutrophus, respectively. Two E. coli clones carrying R. sphaeroides chromosomal fragment of $phbC_{2.4.1}$ in pUC19 were selected from ca. 10,000 colonies. The PHB-producing colonies had an opaque white appearance due to the intracellular accumulation of PHB. The structure of PHB produced by the recombinant E. coli as well as from R. sphaeroides 2.4.1 was confirmed by [$H^{+}$]-nuclear magnetic resonance (NMR) spectroscopy. Restriction analysis of the two pUC19 clones revealed that one insert DNA fragment is contained as a part of the other cloned fragment. An open reading frame of 601 amino acids of $phbC_{2.4.1}$ with approximate M.W. of 66 kDa was found from nucleotide sequence determination of the 2.8-kb SaiI-PstI restriction endonuclease fragment which had been narrowed down to support PHB synthesis through heterologous expression in the E. coli harbouring $phbA,B_{AC}$. The promoter (s) of the $phbC_{2.4.1}$ were localized within a 340-bp DNA region upstream of the $phbC_{2.4.1}$ start codon according to heterologous expression analysis.

• BMB Reports
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• 제39권6호
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• pp.686-695
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• 2006

Interleukin-2 enhancer binding factor 2 (ILF2) was reported to regulate transcription of interleukin-2 (IL-2), a central cytokine in the regulation of T-cell responses. This property of ILF2 was well characterized in human and mammals, but little is known in bony fish. In this paper, an ILF2 homologue was cloned and well characterized from Tetraodon nigrovirid is for the further investigation of the function of ILF2 in bony fish. The full-length Tetraodon ILF2 cDNA was 1380 bp in size and contained an open reading frame (ORF) of 1164 bp that translates into a 387 amino-acid peptide with a molecular weight of 42.9 kDa, a 5' untranslated region (UTR) of 57 bp, and a 3' UTR of 159 bp containing a poly A tail. The deduced peptide of Tetraodon ILF2 shared an overall identity of 58%~93% with other known ILF2 sequences, and contained two N-glycosylation sites, two N-myristoylation sites, one RGD cell attachment sequence, six protein kinase C phosphorylation sites, one amino-terminal RGG-rich single-stranded RNA-binding domain, and a DZF zinc-finger nucleic acid binding domain, most of which were highly conserved through species compared. Constitutive expression of Tetraodon ILF2 was observed in all tissues examined, including gill, gut, head kidney, spleen, liver, brain and heart. The highest expression was detected in heart, followed by liver, head kidney and brain. Stimulation with LPS did not significantly alter the expression of Tetraodon ILF2. Gene organization analysis showed that the Tetraodon ILF2 gene have fifteen exons, one more than other known ILF2 genes in human and mouse. Genes up- and down-stream from the Tetraodon ILF2 were Rpa12, Peroxin-11b, Smad4, Snapap and Txnip homologue, which were different from that in human and mouse.