DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Yang, Ji-Won | - |
dc.contributor.advisor | 양지원 | - |
dc.contributor.author | Jeon, Gyu-Jong | - |
dc.contributor.author | 전규종 | - |
dc.date.accessioned | 2011-12-13T01:35:26Z | - |
dc.date.available | 2011-12-13T01:35:26Z | - |
dc.date.issued | 2001 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=169563&flag=dissertation | - |
dc.identifier.uri | http://hdl.handle.net/10203/28869 | - |
dc.description | 학위논문(박사) - 한국과학기술원 : 화학공학과, 2001.8, [ vii, 124 p. ] | - |
dc.description.abstract | Commercial lipases and proteases were tested for the selective acylation of monosaccharides and sugar alcohol through the transesterification of activated amino acid esters. A commercialized protease from Bacillus licheniformis, Optimase M-440 showed the highest catalytic activity in the transesterification of N-t-Boc-L-Phe-OTFE with D-glucose and D-sorbitol. The broad substrate specificity of Optimase M-440 was effective for the acylation of monosaccharides and sugar alcohols with various amino acid esters. Trifluoroethyl ester of L-phenylalanine was more effective for the transesterification than trichloroethyl ester, cyanomethyl ester and oxime ester. Various solvents were tested for the transesterification with Optimase M-440 as a reaction medium. Optimase M-440 catalyzed the highest conversion in pyridine among the tested organic solvents. Optimase M-440 showed a broad substrate specificity towards trifluoroethyl esters of amino acids and the transesterification of L-form of phenylalanine was faster than D-form. Optimase M-440 exhibited a preferable catalytic activity on the primary hydroxyl group of monosaccharides and sugar alcohols and the regioselectivity was confirmed by the $^13C-NMR$ of the conjugates of amino acid and saccharides. The acylation occurred at the primary hydroxyl groups of D-glucose, and regioselectivity and chemoselectivity of Optimase M-440 was observed in acylation of D-glucosamine. Optimase M-440 catalyzed the acylation of two primary hydroxyl groups of sugar alcohols in spite of the change of reaction conditions. Sugar alcohol conjugates of N-t-Boc-L-Phe-OTFE and N-t-Boc-L-Met-OTFE were synthesized without the acylation of secondary hydroxyl groups. In the transesterification of Nα, Nε-di-t-Boc-L-Lys-OTFE$ and N-t-Boc-L-Asp-diOTFE, Optimase M-440 did not discriminate the glycosidic hydroxyl groups. Only when the glycosidic -OH was blocked, Optimase M-440 could selectively catalyze the acylation of primary hydroxyl group without o... | eng |
dc.language | eng | - |
dc.publisher | 한국과학기술원 | - |
dc.subject | sugar | - |
dc.subject | amino acid | - |
dc.subject | conjugate | - |
dc.subject | enzymatic synthesis | - |
dc.subject | biodegradable polymer | - |
dc.subject | 생분해성 고분자 | - |
dc.subject | 당 | - |
dc.subject | 아미노산 | - |
dc.subject | 콘쥬게이트 | - |
dc.subject | 효소 | - |
dc.title | Enzymatic synthesis of ester-linked amino acid-sugar alcohol conjugates for biodegradable polymers | - |
dc.title.alternative | 생분해성 고분자를 위한 에스터로 연결된 아미노산-당 알코올 콘쥬게이트의 효소적 합성 | - |
dc.type | Thesis(Ph.D) | - |
dc.identifier.CNRN | 169563/325007 | - |
dc.description.department | 한국과학기술원 : 화학공학과, | - |
dc.identifier.uid | 000975338 | - |
dc.contributor.localauthor | Yang, Ji-Won | - |
dc.contributor.localauthor | 양지원 | - |
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