• 대한의용생체공학회:의공학회지
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• 제15권1호
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• pp.89-96
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• 1994

키틴의 글루코사민 단위에 클로로프로판, 산화프로필렌 그리고 클로로프로판 디올을 반응시켜 프로필 키틴(PPC), 히드록시프로필 키틴(HPC), 디히드록시프로필 키틴(DHPC)등의 에테르 형태의 키틴 유도체를 합성하였고, 이들을 99% 포름산에 용해시켜 고분자 농도 30 wt%이상에서 콜레스테릭한 유방성 액정을 형성하였다. 액정이 형성된 용액으로부터 필름을 제조하여 라이소자임이 포함된 유사 체액, pH 1.2, pH 6.7 그리고 pH 8.2 용액에서 in vitro 분해정도를 관찰한 결과 처음 1주일에서 급격하게 분해되었으며 중성 영역에서 큰 무게 감소와 기계적 강도가 감소하였다. 세가지 시료들 중 DHPC가 가장 좋은 생분해 정도를 나타냈다.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.432-438
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• 1996

Native crystalline chitin was hydrolyzed in an agitated bead reaction system using crude chitinase excreted from Aspergillus fumigatus JC-19. The reaction was enhanced significantly, and the concentration and yield of reducing sugar after 48 hours were measured to be 35.42 g/I (w/v) and 0.64, respectively, around 1.86 times higher than those of the conventional system that was carried out without glass beads. The effect of reaction conditions, such as the amounts of chitin, chitinase and glass beads, and the size of glass bead, were examined. Ball milled chitin was also hydrolyzed in the agitated bead reaction system, the conversion yield and reaction rate of ball milled chitin for 24 hours increased up to 0.87 and 48.02 g/I, respectively. Chitinase showed relatively high stability in the agitated bead reaction system, particularly in the presence of enzyme stabilizer, $Ca^{++}$, which played a critical role in preventing the deactivation of chitinase by the physical impact of glass beads. The variations of the structural features of chitin during the reaction were followed by SEM and X-ray diffraction, and the enhanced hydrolysis reaction was caused by both the fragmentation of chitin particles and the destruction of the crystalline structure owing to the synergic effects of the attrition of glass beads and the hydrolytic action of chitinase.

• KSBB Journal
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• 제13권1호
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• pp.44-51
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• 1998

Hydrolysis and adsorption reversibility experiments were run for initial enzyme activity of 4.48, 9.65, 11.19 and 17.14U/mL at a temperature 30$^\circ C$. The chitin particle size corresponded to a mean particle diameter of 0.127mm, and the initial concentration of chitin was 10mg/mL. After approximately 2hrs, the enzyme activity remained constant in a speudo-steady state. The amounts in the bulk [E] and the amounts of enzyme adsorbed on the chitin surface [E] are plotted on Lineweaver-Burk plot to yield a linear relationship with a correlation coefficient of 0.99, a slope of 2.79cm$^-1$ and an intercept of 0.08$\textrm{cm}^2$/U. From this parameters, the values of [E$_T$] and $K_E$ were calculated to be 12.5U/cm$^2$ and 34.88U/mL. respectively, Adsorption isotherm of the enzyme on the particles showed a well developed plateau of 1.35$\times$10$^-3$, 4.72$\times$10$^-3$, 4.42$\times$10$^-3$, 8.58$\times$10$^-3$U/cm$^2$ at 30$^\circ C$. To determine the specificity of chitinase for crystalline chitin, the free energy of adsorption was measured, and its was determined as about -14.62~-18.8kJ/mol.

• 공업화학
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• 제4권2호
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• pp.403-408
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• 1993

키틴과 프로필렌 옥시드를 반응시켜 히드록시프로필 키틴(HPCH)을 얻었고 할로겐화 유기용매내에서 HPCH의 액정형성능을 관찰하였다. 키틴과 HPCH의 고체 $^{13}C$ NMR 스펙트럼 분석 결과 히드록시프로필기의 도입을 확인하였다. 원소분석결과 히드록시프로필기의 치환도는 0.8정도였다. WAXD패턴 측정결과 키틴에 히드록시프로필기가 도입됨에 따라 결정성은 감소하였고 유기용매에 대한 용해도는 증가하였다. HPCH를 디클로로아세트산과 1, 2-디클로로에탄 혼합용매에 녹여 편광현미경으로 관찰한 결과 25% 이상의 용액농도에서 콜레스테릭 액정상에서 전형적으로 관측되는 지문영역이 나타남을 알 수 있었다. 용액의 점도는 시간변화에 따라 감소함을 알 수 있었다.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.237-238
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• 2001

Chitin is the second most abundant natural polymer after cellulose. It is mainly extracted from crustaceous shells and cell walls of fungi, insects and yeast. Chitin is known to be insoluble in most common solvents except for strong acids or N,N-dimethylacetamid because of its rigid crystalline structure through intra- and intermolecular hydrogen bonds. Therefore, different derivatives have been prepared based on chemical and enzymic modification of chitin. (omitted)

• 한국잠사곤충학회지
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• 제40권2호
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• pp.158-162
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• 1998

The chitin was isolated from various kinds of insects such as exuvia of Psacothea hilaris Pascoe, silkworm pupa, Agrius convolvuli or from cuticle of cockroach by treatment with dilute HCI and NaOH. The chemical and crystalline structure was characterized by FT-IR and X-ray diffractometer. All of the chitins extracted from insects showed characteristic ${\alpha}$-chitin peaks at the Bragg angle 2$\theta$=9.3$^{\circ}$, 19.4$^{\circ}$, and 23.5$^{\circ}$by X-ray diffraction analysis. The transition from chitin to chitosan was confirmed by IR spectra and the degree of deacetylation of the crab shell, silkworm pupa, cockroach, and Psacothea hilaris Pascoe was 70.9, 76.4, 75.5, and 74.1%, respectively. The double diffraction peaks of insect chitosan were observed at 2$\theta$=10$^{\circ}$and 20$^{\circ}$, indication the characteristic of hydrated crystalline structure of chitosan.

• 공업화학
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• 제19권5호
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• pp.457-465
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• 2008

인간의 질병을 치료하기 위한 여러 가지 의료 시스템의 개발이 생명공학의 발전과 함께 많은 연구가 이루어지고 있다. 또한 약물이나 유전자와 같은 생리활성물질을 체내에 안전하게 전달할 수 있는 시스템의 개발과 함께 이루어지고 있다. 이러한 시스템에 있어서 가장 중요한 것은 생체적합성 및 생체분해성 그리고 무독성의 특성을 가진 생체의료용 고분자를 개발하는 것이다. 천연고분자물질인 키토산은 좋은 생체적합성과 생체활성의 특성을 가지고 있어서 생체의료용 재료로 심도 있게 고려되어지고 있다. 키토산의 물성은 키틴의 결정성 구조에 따라 다르게 설명되므로 키틴의 구조적 분석에 대한 연구가 생체재료로써의 응용을 위해서 선행되어야 한다. 이러한 관점에서 본 총설에서는 키틴의 결정성 구조 분석, 키토산의 일반적인 물성 그리고 생체의료용 재료로써 저분자량 수용성 키토산의 가능성을 소개하였다. 또한 다양한 기능성기를 이용한 저분자량 수용성 키토산의 화학적인 개질을 약물전달체로써의 가능성을 강조하고 생체이용율의 향상을 위해 수행하였다.

• 공업화학
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• 제3권3호
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• pp.516-521
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• 1992

키틴에 산화프로필렌을 반응시켜 키틴의 수산기에 히드록시프로필기가 치환된 히드록시프로필 키틴(HPCH)을 합성하였다. 여러가지 유기 용매중에서 키틴과 그 유도체의 용해성 시험에서 HPCH가 키틴보다 용해성이 향상되었으며 포름산에서 가장 좋은 용해성을 나타내었다. 포름산을 용매로 HPCH용액을 제조하여 농도를 변화시키면서 편광현미경으로 관찰한 결과 30 wt% 이상의 농도에서 지문형태의 복굴절 현상이 나타났으며, 열분석기(DSC)의 분석에서 열적 특성피크는 관찰되지 않아서 HPCH는 콜레스테릭 구조를 갖는 유방성 액정을 확인할 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제17권4호
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• pp.175-181
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• 1987

To increase the dissolution rate of furosemide, chitin and chitosan which are widely occurring biodegradable natural materials were used as drug carriers. The ground mixtures of furosemide with chitin or chitosan were prepared by grinding in a ball mill. The ground mixture showed a faster and more enhanced dissolution rate than the physical mixture or intact furosemide. The crystalline peaks of furosemide disappeared in the ground mixtures indicating the production of amorphous form. The comparison of infrared spectra of the physical mixture and the ground mixture showed an interaction such as association between the functional groups of furosemide and chitin or chitosan in the molecular level. The weight losses in TGA curves showed all the same patterns. However, the endothermic peak due to the fusion of furosemide in DTA curve disappeared in the ground mixture indicating the different thermal property. The dissolution of furosemide from ground mixtures was fast in the order of chitosan and then chitin. The co-grinding technique with chitin or chitosan provided a promising way enhancing the dissolution rate of practically insoluble drug.

• BMB Reports
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• 제44권6호
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• pp.375-380
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• 2011

Bacillus licheniformis SK-1 naturally produces chitinase 72 (CHI72) with two truncation derivatives at the C-terminus, one with deletion of the chitin binding domain (ChBD), and the other with deletions of both fibronectin type III domain (FnIIID) and ChBD. We constructed deletions mutants of CHI72 with deletion of ChBD (CHI72${\Delta}$ChBD) and deletions of both FnIIID and ChBD (CHI72${\Delta}$FnIIID${\Delta}$ChBD), and studied their activity on soluble, amorphous and crystalline substrates. Interestingly, when equivalent amount of specific activity of each enzyme on soluble substrate was used, the product yield from CHI72-${\Delta}$ChBD and CHI72${\Delta}$FnIIID${\Delta}$ChBD on colloidal chitin was 2.5 and 1.6 fold higher than CHI72, respectively. In contrast, the product yield from CHI72${\Delta}$ChBD and CHI72${\Delta}$FnIIID-${\Delta}$ChBD on ${\beta}$-chitin reduced to 0.7 and 0.5 fold of CHI72, respectively. These results suggest that CHI72 can modulate its substrate specificities through truncations of the functional domains at the C-terminus, producing a mixture of enzymes with elevated efficiency of hydrolysis.