• 농약과학회지
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• 제4권2호
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• pp.29-31
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• 2000

5,6-디히드로-2-메틸-1,4-옥사티인-3-카르복스아닐리드 (1, 카르복신)의 간편하고 경제적인 새로운 합성법과 그 반응 메카니즘을 제시하였다. 아세토아세트아닐리드의 알파-염화물 4 (1당량), 2-메르캡토에탄올 (1.2당량)을 산촉매 파라톨루엔술폰산 일수화물 (0.05당량) 존재하에서 톨루엔 용액 중에서 가열 환류하면서 탈수하여 카르복신 1을 합성하였다. 염화물 4의 헤미티오케탈인 알파 클로로 1,3-옥사티올란 유도체 8의 황원자의 인접기 참여에 의해서 분리할 수 없는 술포니움 이온 9로 전환되고 이어서 보다 안정한 옥소니움 12로 전환되고 이어서 양성자가 제거되어 카르복신 1이 생성됨을 제안하였다.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1789-1796
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• 2007

A ${\beta}$-glucosidase with the molecular mass of 160,000 Da was purified to homogeneity from cell extract of a cellulolytic bacterium, Cellulomonas uda CS1-1. The kinetic parameters ($K_m$ and $V_{max}$) of the enzyme were determined with pNP-cellooligosccharides (DP 1-5) and cellobiose. The molecular orbital theoretical studies on the cellulolytic reactivity between the pNP-cellooligosaccharides as substrate (S) molecules and the purified ${\beta}$-glucosidase (E) were conducted by applying the frontier molecular orbital (FMO) interaction theory. The results of the FMO interaction between E and S molecules verified that the first stage of the reaction was induced by exocyclic cleavage, which occurred in an electrophilic reaction based on a strong charge-controlled reaction between the highest occupied molecular orbital (HOMO) energy of the S molecule and the lowest occupied molecular orbital (LUMO) energy of the hydronium ion ($H_3O^+$), more than endocyclic cleavage, whereas a nucleophilic substitution reaction was induced by an orbital-controlled reaction between the LUMO energy of the oxonium ion ($SH^+$) protonated to the S molecule and the HOMO energy of the $H_2O_2$ molecule. A hypothetic reaction route was proposed with the experimental results in which the enzymatic acid-catalyst hydrolysis reaction of E and S molecules would be progressed via $SN_1$ and $SN_2$ reactions. In addition, the quantitative structure-activity relationships (QSARs) between these kinetic parameters showed that $K_m$ has a significant correlation with hydrophobicity (logP), and specific activity has with dipole moment, respectively.