• BMB Reports
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• 제50권7호
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• pp.367-372
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• 2017

Monoacylglycerol acyltransferase 1 (MGAT) is a microsomal enzyme that catalyzes the synthesis of diacylglycerol (DAG) and triacylglycerol (TAG). However, the subcellular localization and catalytic function domain of this enzyme is poorly understood. In this report, we identified that murine MGAT1 localizes to the endoplasmic reticulum (ER) under normal conditions, whereas MGAT1 co-localize to the lipid droplets (LD) under conditions of enriching fatty acids, contributing to TAG synthesis and LD expansion. For the enzyme activity, both the N-terminal transmembrane domain and catalytic HPHG motif are required. We also show that the transmembrane domain of MGAT1 consists of two hydrophobic regions in the N-terminus, and the consensus sequence FLXLXXXn, a putative neutral lipid-binding domain, exists in the first transmembrane domain. Finally, MGAT1 interacts with DGAT2, which serves to synergistically increase the TAG biosynthesis and LD expansion, leading to enhancement of lipid accumulation in the liver and fat.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.351-354
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• 2002

A number of bis-2-oxo amide triacylglycerol analogues, a recently reported potent human gastric lipase inhibitor and its new analogues, have been prepared starting from 1,3-dibromo-2-propanol utilizing acyl cyanophosphorane methodology as a key step in a convergent manner. The key coupling reaction has been accomplished at -$78^{\circ}C$ between 1,3-diamino-2-propanol derivative and the labile diketo nitriles, derived from acyl cyanotriphenylphosphoranes upon oxidizing with $O_3$, under mild condition in moderate yields.

• Applied Biological Chemistry
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• 제41권6호
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• pp.414-420
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• 1998

식이성지방 n-6/n-3비(1 : 2) 및 포화지방산:단순불포화지방산:다가불포화지방산비(1:1:1)를 일정하게 조정한 조건하에서 n-3계 지방산, ${\alpha}-LA(C_{18:3}),\;EPA(C_{20:5}),\;DHA(C_{22:6})$를 함유시킨 식이를 조제하여 성장기 SD-계 흰쥐 수컷에 2주간 급여하여 간장, 혈청의 Triacylglycerol(TG)농도 및 간장 TG 합성에 관여하는 효소 활성에 대하여 검토하였다. 본 실험에 사용한 EPA 및 DHA 는 순도 98%로서 고도로 정제한 ethyl ester 형태로 식이에 첨가하였다. 그 결과, ${\alpha}-LA$군에 비하여 EPA군 및 DHA군에서 간장 및 혈청 TG 농도는 유의적으로 감소하였으나, 총콜레스테롤 농도는 유의차가 인정되지 않았다. 간장의 인지질 농도는 DHA군에서만 유의적으로 증가하였다. 간장 막 결합성 phosphatidate phosphohydrolas(PAP)성은 간장TG 농도와 같은 경향으로서 EPA와 DHA군에서 유의하게 감소하였으며 Diacylglycerol acyltransferase(DGAT) 활성은 각 군간에는 변화가 없었다. 따라서, 간장TG 농도와 간장 막결합성 PAP활성과의 사이에 높은 상관관계(r=0.84)를 나타내어 간장TG 합성억제가 인정되었다. 지방산 합성계 효소의 활성도는 EPA및 DHA군에서 감소하였다. 이상의 결과로부터 n-3계 지방산, EPA 및 DHA에 의한 간장 및 혈청 TG 농도의 감소는 막 결합형 PAE 활성과 저해에 의한 간장TG 합성 및 지방산 합성 저해가 관여하는 것이 시사되었다.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.242-250
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• 2023

Comparative gene identification-58 (CGI-58) is an activating protein of triacylglycerol (TAG) lipase. It has a variety of catalytic activities whereby it may play different roles in diverse organisms. In this study, a homolog of CGI-58 in Phaeodactylum tricornutum (PtCGI-58) was identified. PtCGI-58 was localized in mitochondria by GFP fusion protein analysis, which is different from the reported subcellular localization of CGI-58 in animals and plants. Respectively, PtCGI-58 overexpression resulted in increased neutral lipid content and TAG accumulation by 42-46% and 21-32%. Likewise, it also increased the relative content of eicosapentaenoic acid (EPA), and in particular, the EPA content in TAGs almost doubled. Transcript levels of genes involved in de novo fatty acid synthesis and mitochondrial β-oxidation were significantly upregulated in PtCGI-58 overexpression strains compared with wild-type cells. Our findings suggest that PtCGI-58 may mediate the breakdown of lipids in mitochondria and the recycling of acyl chains derived from mitochondrial β-oxidation into TAG biosynthesis. Moreover, this study potentially illuminates new functions for CGI-58 in lipid homeostasis and provides a strategy to enrich EPA in algal TAGs.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.337-345
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• 2021

Lipase (triacylglycerol lipase, EC 3.1.1.3) is an enzyme capable of hydrolyzing triacylglycerol, to produce fatty acids and glycerol and reverse the reaction of triacylglycerol synthesis from fatty acids and glycerol through transesterification. Applications of lipase are quite widespread in the industrial sector, including in the detergent, paper, dairy, and food industries, as well as for biodiesel synthesis. Lipases by yeasts have attracted industrial attention because of their fast production times and high stability. In a previous study, a lipase-producing yeast isolate was identified as Zygosaccharomyces mellis SG1.2 and had a productivity of 24.56 U/mg of biomass. This productivity value has the potential to be a new source of lipase, besides Yarrowia lypolitica which has been known as a lipase producer with a productivity of 0.758 U/mg. Lipase production by Z. mellis SG1.2 needs to be increased by optimizing the production medium. The aims of this study were to determine the significant component of the medium for lipase production and methods to increase lipase production using the optimum medium. The two methods used for the statistical optimization of production medium were Taguchi and RSM (Response Surface Methodology). The data obtained were analyzed using Minitab 18 and SPSS 23 software. The most significant factors which affected lipase productivity were olive oil and peptones. The optimum medium composition consisted of 1.02% olive oil, 2.19% peptone, 0.05% MgSO₄·7H₂O, 0.05% KCl, and 0.2% K₂HPO₄. The optimum medium was able to increase the lipase productivity of Z. mellis SG1.2 to 1.8-fold times the productivity before optimization.

• 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.375.4-376
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• 2002

Acyl CoA:diacylglycerol acyltransferase (DGAT) is a key enzyme involved in triacylglycerol synthesis. Too much accumulation of triacylglycerol in certain organs and tissues of the body causes high risk conditions of fatty liver. obesity and hypertriglyceridemia. leading to serious diseases of atherosclerosis. Therefore, DGAT inhibition may be worthwhile strategy for the treatment of triglyceride metabolism disorders. such as obesity or hypertriglyceridemia. (omitted)

• 농업과학연구
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• 제40권4호
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• pp.367-375
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• 2013

The enzymatic interesterification was performed to produce structured lipids (SLs) with palm mid fraction (PMF) and stearic ethyl ester (STEE) for 1, 3, 6, 9, 12 and 15 hr at $80^{\circ}C$. The reaction was catalyzed by Lipozyme TLIM (immobilized lipase from Thermomyces lanuginosus, amount of 20% by weight of total substrates) in a shaking water bath set at 180 rpm. The optimum condition for synthesis of asymmetric SLs were: substrate molar ratio 1:0.5 (PMF:STEE, by weight), reaction time 6 hr, enzyme 20% (wt%, water activity=0.085) of total substrate and reaction temperature $80^{\circ}C$. After reaction at optimized condition, triacylglycerols (symmetrical and asymmetrical TAGs) from reactants were isolated. POP/PPO (1,3-palmitoyl-2-oleoyl glycerol or 1,2-palmitoyl-3-oleoyl glycerol), POS/PSO (palmitoyl-oleoyl-stearoyl glycerol or palmitoyl-stearoyl-oleoyl glycerol), SOS/SSO (1,3-stearoyl-2-oleoyl glycerol or 1,2-stearoyl-3-oleoyl glycerol) were obtained by solvent fractionation. Finally, refined SLs contained stearic acid of 16.91%. Solid fat index and thermogram of the refined SLs were obtained using differential scanning calorimetry. The degree of asymmetric triacylglycerol in the refined SLs was analyzed by Ag-HPLC equipped with evaporated light scattering detector (ELSD). The refined SLs consisted of symmetric TAG of 41.15 area% and asymmetric TAG of 58.85 area%.

• The Korean Journal of Ecology
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• 제19권1호
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• pp.21-29
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• 1996

Variation in triacylglycerols(TGs) and fatty acids in Fucus serratus was analyzed for a period of one year. TGs were more concentrated during the summer(2.8mg/g dw)and autumn(2.6mg/g dw) than during the spring (0,7mg/g dw)and winter (0.5mg/g dw). The dominant fatty acides in total liqid were palmitic acid ($C_{16:0}$, 24.1%), oleic acid (($C_{18:1}$, 22.4%) and arachidonic acid (($C_{20:4}$, 14.4%) but the dominant ones in TG were $C_{16:0}$(22.8%), $C_{18:1}$(36.4%) and $C_{18:2}$(linoleic acid, 16.4%). The levels of $C_16$ fatty acids were high in winter while $C_18$ in summer and autumn. The polyunsaturated fatty acids (UFAs) were more abundant in the $C_20$ series, while the UFAs of the $C_16$ were low. Especially, the amount of arachidonic acid ($C_{20:4}$, 14.4% of total fatty acids (TFA) was more abundant than that of eicosapentaenoic acid ($C_{20:5}$, 10.4% of TFA). The amount of $C_{20:4}$ and $C_{20:5}$,in TG was 9.2% and 4.8%, respectively. These UFAs in total lipid were thus higher than TG. Therefore, the synthesis of TG and fatty acid was stimulated by the alternation of emersion and submersion of thalli from sea water and eco-physiological conditions during summer: high temperature and light, and low concentration of nitrogen.

• Journal of Microbiology and Biotechnology
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• 제33권12호
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• pp.1563-1575
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• 2023

Acyl-coenzyme A (CoA):diacylglycerol acyltransferase 2 (DGAT2) catalyzes the last stage of triacylglycerol (TAG) synthesis, a process that forms ester bonds with diacylglycerols (DAG) and fatty acyl-CoA substrates. The enzymatic role of Dgat2 has been studied in various biological species. Still, the full description of how Dgat2 channels fatty acids in skeletal myocytes and the consequence thereof in glucose uptake have yet to be well established. Therefore, this study explored the mediating role of Dgat2 in glucose uptake and fatty acid partitioning under short interfering ribonucleic acid (siRNA)-mediated Dgat2 knockdown conditions. Cells transfected with Dgat2 siRNA downregulated glucose transporter type 4 (Glut4) messenger RNA (mRNA) expression and decreased the cellular uptake of [1-¹⁴C]-labeled 2-deoxyglucose up to 24.3% (p < 0.05). Suppression of Dgat2 deteriorated insulin-induced Akt phosphorylation. Dgat2 siRNA reduced [1-¹⁴C]-labeled oleic acid incorporation into TAG, but increased the level of [1-¹⁴C]-labeled free fatty acids at 3 h after initial fatty acid loading. In an experiment of chasing radioisotope-labeled fatty acids, Dgat2 suppression augmented the level of cellular free fatty acids. It decreased the level of re-esterification of free fatty acids to TAG by 67.6% during the chase period, and the remaining pulses of phospholipids and cholesteryl esters were decreased by 34.5% and 61%, respectively. Incorporating labeled fatty acids into beta-oxidation products increased in Dgat2 siRNA transfected cells without gene expression involving fatty acid oxidation. These results indicate that Dgat2 has regulatory function in glucose uptake, possibly through the reaction of TAG with endogenously released or recycled fatty acids.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.85-94
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• 1994

Lipase (triacylglycerol hydrolase, EC 3.1.1.3) is able to catalyze the hydrolysis of ester bonds of triacylglycerols at the interface between aqueous phase and organic phase containing substrate. With the rapid development of lipid biotechnology, lipase-catalyzed hydrolysis of lipids has a great concern from the industrial point of view. Owing to the reversible nature of the lipase, the reactions are also applied for glyceride synthesis, interesterification and resolution of racemic mixtures into optically active alcohols or acids. For all applications of the lipases, a reliable method for the determination of enzyme activity is required. Precise quantitative determination of its activity is essential as the basis of research and development of the bioprocess involving the enzyme. This article reviews the existing literature on the detection and determination of lipase activity from microbial, mammalian and plant sources.