• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.672-679
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• 2022

Microbial lipases are used widely in the synthesis of various compounds due to their substrate specificity and position specificity. 4-Ethyl malate (4-EM) made from diethyl malate (DEM) is an important starting material used to make argon fluoride (ArF) photoresist. We tested several microbial lipases and found that Photobacterium lipolyticum M37 lipase position-specifically hydrolyzed DEM to produce 4-EM. We purified the reaction product through silica gel chromatography and confirmed that it was 4-EM through nuclear magnetic resonance analysis. To mass-produce 4-EM, DEM hydrolysis reaction was performed using an enzyme reactor system that could automatically control the temperature and pH. Effects of temperature and pH on the reaction process were investigated. As a result, 50℃ and pH 4.0 were confirmed as optimal reaction conditions, meaning that M37 was specifically an acid lipase. When the substrate concentration was increased to 6% corresponding to 0.32 M, the reaction yield reached almost 100%. When the substrate concentration was further increased to 12%, the reaction yield was 81%. This enzyme reactor system and position-specific M37 lipase can be used to mass-produce 4-EM, which is required to synthesize ArF photoresist.

• 약학회지
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• 제50권4호
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• pp.268-271
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• 2006

Protein kinase UL97 is an unusual protein kinase that can phosphorylate nucleoside analogs as well as protein/peptide. Previously we found a H2B-derived peptide, KESYSVYVYKV and reported that the P+5 position (K) is important. To further understand the substrate specificity at the P+5 position, we introduced spot assay system and showed that a peptide containing K residue among other amino acids at the P+5 position is the best substrate. Also other residues such as M, I, L, or G are good enough to be substrate of UL97. This result may aid the discovery of a new antiviral inhibitor.

• KSBB Journal
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• 제19권6호
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• pp.489-493
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• 2004

Candida cylindracea 유래의 Lipase-OF 360,000를 사용하여 물고기 기름을 구성하고 있는 여러 종류의 지방산의 아실 체인 특성과 가수분해율 사이의 함수관계를 규명하였다. 이중결합수와 이중결합이 시작되는 위치, 즉 (n-3), (n-7) 및 (n-9)이 동일할 경우, Lipase-OF 360,000에 의한 지방산의 가수분해율은 지방산을 구성하고 있는 탄소수의 증가에 따라 가수분해율이 감소하는 아실체인 특이성을 나타내었다. 이중결합이 시작되는 탄소의 위치 또한 Lipase-OF 360,000의 가수분해 특이성에 영향을 끼쳤다. 이 외에 Lipase-OF 360,000은 지방산의 탄소수와 이중결합이 시작되는 위치가 동일할 경우, 이중결합수가 증가하면 가수분해율이 감소하는 아실 체인 특이성도 나타내었다. 또한 본 연구에서는 물고기 기름을 구성하고 있는 각 지방산의 가수분해율을 시간의 함수로 제시함으로서 원하는 지방산을 미반응 글리세라이드 혼합물 내로 농축시키는 공정개발의 기초 자료로 활용할 수 있도록 하였다.

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.953-957
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• 2001

The specificity of conjugation site for coating ligands was investigated using toluene-bovine serum albumin (BSA) conjugates in which BSA was conjugated at the position of o-, m-, and ${\rho}-toluic$ acid. Toluene-BSA conjugated at ${\rho}-position$ showed a binding activity of about 89-95%, whereas, those conjugated at o- and m-position of toluene exhibited a binding activity of 5 and 11%, respectively. On the basis of the above result, coating ligands with various proteins (OVA, BSA, KLH) were compared by conjugating with $\rho-toluic$ acid, and toluene-KLH was considered as the best coating ligand for this ELISA. Indirect competitive ELISA method was developed using anti-toluene antibody and $\rho-position$ conjugated toluene-KLH. The dose-response curve constructed after kinetic and optimization studies showed a 1${\times}$10-4 - 1${\times}$102 mM detectable response range with 0.1 ${\mu}M$ detectability. In specificity test of the antibody, the binding capabilities of aromatic compounds substituted with nitro-, alkyl-, chloro-, and hydroxyl group were larger rather than those of aromatic compounds (benzene, toluene and xylene) themselves. Also, tests with soil and water samples that had been spiked with toluene resulted in 102.7-113.7% recovery.

• 치과방사선
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• 제21권2호
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• pp.327-336
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• 1991

The purpose of this study was to evaluate the validity among the clinical, transcraial radiographic and MRI diagnosis in internal derangement of the temporomandibular joint. Fourty two temporomandibular joints were assessed in twenty one patients who visited the dental department of Chonnam National University Hospital with the complaint of temporomandibular disorder from Oct. 1990 to Oct. 1991. The results were as follows: 1. In the clinically symptomatic 29 TMJs, 26 (89.7%) joints reveal disc displacement and 3 (10.3%) joints reveal normal disc position on MRI. The sensitivity of clinical diagnosis was 0.77, and the specificity was 0.63. 2. In the normal 22 TMJs on the trans cranial radiographic finding, 16 (72.7%) joints reveal disc displacement, and 6 (27.3%) joints reveal normal disc position on MRI. In the abnormal 20 TMJs on the transcranial radiographic finding, 18 (90%) joints reveal disc displacement, and 2 (10%) joints reveal normal disc position on MRI. The sensitivity of trans cranial radio- graph was 0.53, and the specificity was 0.75.

• KSBB Journal
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• 제14권3호
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• pp.259-263
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• 1999

물고기 기름에 대한 Aspergillus oryzae 유래의 Lipolase-100T의 가수분해 특성을 규명하였다. Lipolase-100T는 트리글리세라이드의 1과 3의 위치에 작용하여 이 위치에 결합되어 있는 아실 체인을 유리지방산으로 가수분해시키는 1,3-위채특이성을 보였다. 또한 Lipolase-100T는 물고기 기름을 구성하는 다중불포화지방산 보다 포화지방산을 쉽게 가수분해시키는 특성도 나타내었다. 이 특성으로 인하여 가수분해 시간에 따라서 생성되는 글리세라이드 혼합물내의 다중 불포화 지방산중 n-3 PUFAs인 C16:4, C20:5 및 C22:6의 농도는 모두 증가하였으며 특히 C22:6의 농도증가가 가장 뚜렷하였다. 이 결과로부터 물고기 기름을 구성하는 n-3 PUFAs는 트리글리세라이드의 2번 위치에 결합하고 있음을 알 수 있었다. 지방산의 결합위치특이성과 Lipolase-100T 1,3-위치특이성으로 인하여 Lipolase-100T를 반응물의 0.4 wt%사용하여 물고기 기름을 120시간 가수분해 시켰을 때 생성된 글리세라이드 혼합물내의 n-3 PUFAs농도는 50 wt%까지 상승하였다.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.502-506
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• 2000

In order to determine the position and the content of fatty acids sttached to glycerides and the migration degree of fatty acids in the migration reaction, fish oil was hydroyzed with lipolase-100T which was derived from Aspergillus oryzae. The content of fatty acids in the glyceride mixture was analyzed and compared with that of fish oil. The amounts of fatty acid in a 2-position and the migration degree of the fatty acid in 2,3-DG (diglyceride) and 2-MG (monolyceride) were carefully calculated. The results showed that approximately 95% (w/w) of DHA (docosahexanoic acid) and 65% of EPA(eicosapentaenoic acid) were attached to the 2-position of glycerides in fish oil. Approximately 87% (w/w) of DHA and 75% of EPA remained in 2,3-DG, and 88% of DHA and 65% of EPA in 2-MG were not involved in the migration reaction.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.624-630
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• 1999

In order to investigate the position of various fatty acids attached to glycerol and the specificity of Lipolase-100T, hydrolysis of fish oil was carried out with Lipolase-100T derived from Aspergillus oryzae. The amounts of free fatty acids produced from triglyceride, 1,2(2,3)-diglyceride, 1,3-diglyceride, and 2-monoglyceride and conversion rates of 1,2(2,3)-diglyceride to 1,3-diglyceride and 2-monoglyceride to 1(3)-monoglyceride were also calculated. The ratio of 1,2-diglyceride content to 1,3-diglyceride was higher than 70 in the early period of hydrolysis. The fatty acid content of the glyceride mixture after 72 h of hydrolysis was compared with that of fish oil, and it was found that polyunsaturated fatty acids such as C16:4, C20:4 n-3, C20:5 n-3, C21:5 n-3, C22:5 n-3 and C22:6 n-3 were located in the 2-position of glycerol. Material balance of each component in the hydrolysis system was written to obtain a set of simultaneous linear equations. The theoretical quantity of free fatty acids produced from triglyceride, 1,2-diglyceride, 1,3-diglyceride, and monoglyceride, respectively, were calculated by solving the linear equation system. The conversion rate of 1,2(2,3)-diglyceride to 1,3-diglyceride and that of 2-monoglyceride to 1(3)-monoglyceride were also obtained. The results showed that the migration rate of 1,2(2,3)-diglyceride to 1,3-diglyceride was higher than the hydrolysis rate of 1,2(2,3)-diglyceride to 2-monoglyceride and the conversion rate of 2-monoglyceride to 1(3)-monoglyceride was extremely low.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1845-1854
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• 2016

The transglycosylation activity of amylosucrase (ASase) has received significant attention owing to its use of an inexpensive donor, sucrose, and broad acceptor specificity, including glycone and aglycone compounds. The transglycosylation reaction of recombinant ASase from Deinococcus radiopugnans (DRpAS) was investigated using various phenolic compounds, and quercetin-3-O-rutinoside (rutin) was found to be the most suitable acceptor molecule used by DRpAS. Two amino acid residues in DRpAS variants (DRpAS Q299K and DRpAS Q299R), assumed to be involved in acceptor binding, were constructed by site-directed mutagenesis. Intriguingly, DRpAS Q299K and DRpAS Q299R produced 10-fold and 4-fold higher levels of rutin transglycosylation product than did the wild-type (WT) DRpAS, respectively. According to in silico molecular docking analysis, the lysine residue at position 299 in the mutants enables rutin to more easily position inside the active pocket of the mutant enzyme than in that of the WT, due to conformational changes in loop 4.

• 약학회지
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• 제52권6호
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• pp.466-470
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• 2008

Human cytomegalovirus expresses an unusual protein kinase UL97, a member of ${H_V}{U_L}$ family of protein kinase. UL97 can phosphorylate nucleoside analogs such as ganciclovir as well as protein/peptide. It has previously been reported that UL97 is able to phosphorylate a KESYSVYVYKV peptide and that P+5 position (K) is important. We examined the extent of contribution of other positions (P-4 through P+6) of the peptide to be substrate of UL97 using alanine substituted peptides (Ala scanning) and deleted peptides. The result suggested that the E (P-2) is negative effect and P+5 (K) is still important. The peptide YSVYVYK is the shortest substrate enough to show high activity, which could be a starting point to develop peptidomimetic drug. This study would give important information to deeply understand the substrate specificity of UL97 and develop an antiviral drug using the small peptide identified here.