• BMB Reports
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• v.50 no.7
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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.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.211-216
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• 2004

Mono-and diacylglycerol-enriched oil was produced from corn oil through enzymatic glycerolysis using 1,3-specific immobilized lipase in solvent-free system and stirred-tank batch reactor. HPLC analysis revealed enriched oil was respectively composed of: 45.05, 16.27, 23.05, and 14.98% triacylglycerol, 1,3-diacylglycerol, 1,2-diacylglycerol, and monoacylglycerol; 13.21, 0.15, 2.02, 34.36, 49.12, and 1.14 mol% palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids; and 0.014, 0.029, 0.010 and 0.053% ${\alpha},\;{\gamma},\;{\delta}-$, and total tocopherols. Physiochemical and melting properties of enriched oil were evaluated. Oxidative stability study revealed enriched oil showed higher peroxide and p-anisidine values than corn oil. Rosemary extracts (100 to 300 ppm) reduce oxidation.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.311-311
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• 2005

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.717-722
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• 2004

Response surface methodology was used to optimize production conditions of monoacylglycerol (MAG) and diacylglycerols (DAG) from corn oil by enzymic glycerolysis. Contents of $1,3-DAG\;(Y_1),\;1,2-DAG\;(Y_2),\;total\;DAG\;(Y_3),\;MAG\;(Y_4)$, and total $DAG+MAG\;(Y_5)$ were obtained. Conditions were optimized using central composite design with incubation temperature $(35-75^{\circ}C,\;X_1)$, incubation time (1-11 hr, $X_2$), and amount of hexane added (0-2 mL, $X_3$) as three variables. Content of 1,3-DAG was maximized by 20.43 area% at incubation temperature of $44.92^{\circ}C$, incubation time of 10.24 hr, and hexane content of 1.16 mL, whereas that of 1,2-DAG (26.78 area%) was maximized at $56.32^{\circ}C$, 6.95 hr, and 1.04 mL, respectively. Predicted maximum total DAG content was 45.09 area% at $53.82^{\circ}C$, 8.03 hr, and 1.08 mL, while production conditions of MAG (9.57 arae%) were $64.14^{\circ}C$, 7.00 hr, and 0.13 mL. At variables of $54.07^{\circ}C$, 7.98 hr, and 1.02 mL, maximum content of total DAG+MAG predicted by RSM was 53.54 area%.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.16-23
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• 2009

Lipids were extracted from marine rotifer, Brachionus rotundiformis in order to examine the functionality of lipid enzymatic modification. The fatty acids, palmitic, linoleic, oleic and stearic acids were the dominant forms accounting for approximately 35.8%, 21.5%, 15.9% and 7.7% of the total lipid content, respectively. Lipid fractions were categorized as neutral lipids (38.5%), glycolipids (45.9%) and phospholipids (17.6%), and after extraction from the rotifer were isolated by thin-layer chromatography (TLC) as free fatty acids (FFA), monoacylglycerol (MAG), diacylglycerol (DAG) and triacylglycerol (TAG). The production of polyunsaturated fatty acid (PUFA) concentrate from rotifer lipids was studied using lipase-catalyzed hydrolysis. In addition, rotifer lipids were modified by hydrolysis using lipases such as porcine pancreas, Candida rugosa and Rhizomucor miehei. The lipase from Rhizomucor miehei was effective in extracting linoleic acid (C 18:2), while the lipase from Candida rugosa was effective in palmitic acid (C16:0) extraction.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.141.2-141
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• 2003

고도불포화지방산 중 EPA(eicosapentaenoic acid)와 DHA(docosahexaenoic acid)는 여러 가지 생리활성 효과를 나타내는 것으로 알려져 있으며, 최근 관심이 주목되고 있다. 본 실험에서는 특히 DHA의 함량이 높은 해양미생물, 즉 조류(microalgae)인 Schizochytrium sp.에서 얻어진 DHA powder로부터 두 가지 방법으로 유지를 추출한 뒤 그 성질을 비교.분석하였다. 먼저, 8$0^{\circ}C$, soxhlet extractor로부터 6시간 동안 추출하고, 55$^{\circ}C$, shaking water bath로부터 같은 시간 동안 추출한 결과, 각각 25.5, 24.0%의 수율을 나타내었다. GC에 의한 지방산 조성 분석 결과, soxhlet extractor에서 추출한 경우, palmitic acid, DHA가 각각 30.98, 30.04 mol%로 주요 지방산인 것으로 나타났으며, shaking water bath에서 추출된 유지는 그 함량이 각각 31.44, 34.78 mol%를 나타내었다. 또한 pancreatic lipase에 의한 가수분해를 통해 sn-2 위치의 지방산 조성 분석 결과, DHA가 sn-2 위치에 주로 함유되어있는 것으로 조사되었다. 한편, HPLC-ELSD system을 이용하여 중성지방의 구성 성분을 분석 결과, 유지의 99%이상이 TAG(triacylglycerol) 형태로 이루어져 있었으며, 소량의 MAG(monoacylglycerol) 존재를 확인할 수 있었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.803-809
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• 2004

Monoacylglycerol (MG) and diacylglycerol (DG), as the components of enzymatically synthesized functional oil, were produced by glycerolysis of rice bran oil and glycerol using IM60 (immobilized lipase) in a stirredbatch reactor at 6$0^{\circ}C$ for 72 hours. After glycerolysis, the contents of triacylglycerol (TG), DG and MG in the produced functional oil were 41.71%,46.19%, and 11.15%, respectively. The functional oil also contained Phytosterols (2.04$\pm$0.17 mg/g), ${\gamma}$ -oryzanol (1.06$\pm$0.04 mg/g) and $\alpha$ -tocopherol (0.13$\pm$0.04 mg/g). In animal experiment the dietary effects of functional oil on hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activities of the high cholesterol and high fat (HCHF)-fed mice were investigated. In functional oil-fed group, the liver ACAT activity was significantly lowered than in HCHF and corn oil-fed groups (p < 0.05). This results suggested that the synthesized functional oil may have an atheroproteetive effect by inhibiting ACAT activity.

• Journal of Animal Science and Technology
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• v.55 no.4
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• pp.303-314
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• 2013

Knowledge regarding lipid catabolism has been of great interest in the field of animal sciences. In the livestock industry, excess fat accretion in meat is costly to the producer and undesirable to the consumer. However, intramuscular fat (marbling) is desirable to enhance carcass and product quality. The manipulation of lipid content to meet the goals of animal production requires an understanding of the detailed mechanisms of lipid catabolism to help meticulously design nutritional, pharmacological, and physiological approaches to regulate fat accretion. The concept of a basic system of lipases and their co-regulators has been identified. The major lipases cleave triacylglycerol (TAG) stored in lipid droplets in a sequential manner. In adipose tissue, adipose triglyceride lipase (ATGL) performs the first and rate-limiting step of TAG breakdown through hydrolysis at the sn-1 position of TAG to release a non-esterified fatty acid (NEFA) and diacylglycerol (DAG). Subsequently, cleavage of DAG occurs via the rate-limiting enzyme hormone-sensitive lipase (HSL) for DAG catabolism, which is followed by monoglyceride lipase (MGL) for monoacylglycerol (MAG) hydrolysis. Recent identification of the co-activator (Comparative Gene Identification-58) and inhibitor [G(0)/G(1) Switch Gene 2] of ATGL have helped elucidate this important initial step of TAG breakdown, while also generating more questions. Additionally, the roles of these lipolysis-related enzymes in muscle, liver and skin tissue have also been found to be of great importance for the investigation of systemic lipolytic regulation.

• Korean journal of food and cookery science
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• v.23 no.2 s.98
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• pp.180-186
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• 2007

In this study, we examined the effects of different water activities (Aw: 0.3, 0.5, and 0.8) on the lipid composition and oxidation of wheat flour after 28 days of storage in the dark at $60^{\circ}$C. The lipid content of the flour was 2.7%, and had decreased significantly (p<0.05) at the end of the storage period. Decrease in monoacylglycerol and increase in free fatty acids were observed, however, phosphatidic acid, phosphatidylglycerol, and phosphatidylinositiol were not detected after storage. Phosphatidylehtanolamine was more stable than phosphatidylcholine during the dark storage of flour. The flour lipids consisted of palmitic (18%), stearic (1%), oleic (14%), linoleic (63%), and linolenic (4%) acids, and the relative content of linolenic acid decreased after 28 days of storage. The conjugated dienoic acid content of the flour lipid had increased due to lipid oxidation during dark storage. Hydrolysis of neutral lipids and glycolipids, and lipid oxidation, were higher in the flour stored at Aw 0.8 than in the flour stored at Aw 0.3 or 0.5.

• The Journal of Internal Korean Medicine
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• v.37 no.4
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• pp.579-590
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• 2016

Objectives: This study aimed to investigate the impact of Ephedra sinica pharmacopuncture on the weight and lipid metabolism of obese mice.Methods: Obesity was induced in male C57BL/6 mice by a 60% fat diet. The animals were divided into three groups (n=5) fed a normal diet, high-fat diet, and high-fat diet with Ephedra sinica pharmacopuncture. After 13 wk, fasting blood sugar levels were measured in each group, and oral glucose tolerance tests were conducted. After 15 wk, body weight, epididymal fat pad weight, subcutaneous fat pad weight, and serum lipid and gene expression of hormone sensitive lipase (HSL), adipose triglyceride lipase (ATGL), monoacylglycerol lipase (MGL), perilipin, and peroxisome proliferator-activated receptor (PPAR)-γ were measured in each group.Results: In the Ephedra group, body weight, fasting blood sugar, and oral glucose tolerance were significantly decreased. In addition, in the Ephedra group, the gene expression of HSL was significantly increased, whereas that of perilipin was significantly decreased.Conclusions: These results provide evidence that E. sinicapharmacopuncture affects obesity and obesity-induced metabolic syndrome, including insulin resistance and dyslipidemia, by activating lipolysis via the HSL pathway in adipose tissue.