1,2-diacylglycerol

1,2-ジアシルグリセロール

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/08/01 04:34:45」(JST)

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Chemical structure of the diglyceride 1-palmitoyl-2-oleoyl-glycerol

A diglyceride, or a diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. One example, shown on the right, is 1-palmitoyl-2-oleoyl-glycerol, which contains side-chains derived from palmitic acid and oleic acid. Diacylglycerols can also have many different combinations of fatty acids attached at both the C-1 and C-2 positions.

Food additive

Mono- and diglycerides (E471) are common food additives used to blend together certain ingredients, such as oil and water, which would not otherwise blend well. The values given in the nutritional labels for total fat, saturated fat, and trans fat do not include those present in mono- and diglycerides^{[citation needed]}.

The commercial source may be either animal (cow- or hog-derived) or vegetable, derived primarily from partially hydrogenated soy bean and canola oil.^{[citation needed]} They may also be synthetically produced. They are often found in bakery products, beverages, ice cream, peanut butter, chewing gum, shortening, whipped toppings, margarine, confections, and candies.

Biological functions

Protein kinase C activation

PIP2 cleavage to IP3 and DAG initiates intracellular calcium release and PKC activation.

In biochemical signaling, diacylglycerol functions as a second messenger signaling lipid, and is a product of the hydrolysis of the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) by the enzyme phospholipase C (PLC) (a membrane-bound enzyme) that, through the same reaction, produces inositol trisphosphate (IP₃). Although inositol trisphosphate diffuses into the cytosol, diacylglycerol remains within the plasma membrane, due to its hydrophobic properties. IP₃ stimulates the release of calcium ions from the smooth endoplasmic reticulum, whereas DAG is a physiological activator of protein kinase C (PKC). The production of DAG in the membrane facilitates translocation of PKC from the cytosol to the plasma membrane.

Diacylglycerol can be mimicked by the tumor-promoting compounds phorbol esters.

Other

In addition to activating PKC, diacylglycerol has a number of other functions in the cell:

• a source for prostaglandins
• a precursor of the endocannabinoid 2-arachidonoylglycerol
• an activator of a subfamily of transient receptor potential canonical (TRPC) cation channels, TRPC3/6/7.

Metabolism

glycerol-3-phosphate

Synthesis of diacylglycerol begins with glycerol-3-phosphate, which is derived primarily from dihydroxyacetone phosphate, a product of glycolysis (usually in the cytoplasm of liver or adipose tissue cells). Glycerol-3-phosphate is first acylated with acyl-coenzyme A (acyl-CoA) to form lysophosphatidic acid, which is then acylated with another molecule of acyl-CoA to yield phosphatidic acid. Phosphatidic acid is then de-phosphorylated to form diacylglycerol.

Diacylglycerol is a precursor to triacylglycerol (triglyceride), which is formed in the addition of a third fatty acid to the diacylglycerol under the catalysis of diglyceride acyltransferase.

Since diacylglycerol is synthesized via phosphatidic acid, it will usually contain a saturated fatty acid at the C-1 position on the glycerol moiety and an unsaturated fatty acid at the C-2 position.

Diacylglycerol can be degraded to phosphatidic acid by diacylglycerol kinase.

See also

• Lipids
• Archaeol

References

UpToDate Contents

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• 1. プロテインキナーゼCと糖尿病の血管合併症 protein kinase c and the vascular complications of diabetes mellitus
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• 4. T細胞受容体シグナル伝達 t cell receptor signaling
• 5. 運動以外の好中球機能 neutrophil functions other than movement

English Journal

• The effects of an inhibitor of diglyceride lipase on collagen-induced platelet activation.

• Jackson EC, Ortar G, McNicol A.Author information Department of Oral Biology (E.C.G.J., A.M.) and Pharmacology and Therapeutics (A.M.), University of Manitoba, Winnipeg, Manitoba, Canada; and Dipartimento di Chimica e Tecnologie del Farmaco Università di Roma 'Sapienza', Roma, Italy (G.O.).AbstractHuman platelet activation by collagen occurs in a dose-dependent manner. High concentrations of collagen bind to a pair of receptors, the α2β1 integrin and glycoprotein (GP)VI/Fc-receptor γ-chain (FcRγ), which stimulate a cascade of events including Syk, LAT, Btk, Gads, and phospholipase Cγ2, leading to calcium release and protein kinase C (PKC) activation. Calcium and PKC are responsible for a range of platelet responses including exocytosis and aggregation, as well as the cytosolic phospholipase A2 (cPLA2)-mediated release of arachidonic acid, which is converted to thromboxane (Tx)A2. In contrast, low concentrations of collagen are acutely aspirin-sensitive, and calcium release and aggregation are TxA2-dependent. Under these conditions, cPLA2 is not involved and it has been suggested that phospholipase C generates 1,2-diacylglycerol (DG) from which arachidonic acid is liberated by diglyceride lipase (DGL). Here a novel DGL blocker (OMDM-188) inhibited collagen-, but not arachidonic acid-induced aggregation and TxA2 synthesis. Furthermore, OMDM-188 inhibited collagen-induced arachidonic acid release. Finally OMDM-188 inhibited collagen-induced p38(MAPK) phosphorylation, but not extracellular signal-regulated kinase (ERK) phosphorylation, with no effect on the phosphorylation of either enzyme in response to arachidonic acid. Taken together, these data suggest a role for a pathway involving phospholipase C liberating DG from membrane phospholipids in response to minimally activating concentrations of collagen. The DG serves as a substrate for DGL, potentially under the regulations of p38(MAPK), to release arachidonic acid, which is subsequently converted to TxA2, which mediates the final platelet response.
• The Journal of pharmacology and experimental therapeutics.J Pharmacol Exp Ther.2013 Dec;347(3):582-8. doi: 10.1124/jpet.113.205591. Epub 2013 Sep 16.
• Human platelet activation by collagen occurs in a dose-dependent manner. High concentrations of collagen bind to a pair of receptors, the α2β1 integrin and glycoprotein (GP)VI/Fc-receptor γ-chain (FcRγ), which stimulate a cascade of events including Syk, LAT, Btk, Gads, and phospholipase Cγ2, l
• PMID 24042163

• Activation of Src and release of intracellular calcium by phosphatidic acid during Xenopus laevis fertilization.

• Bates RC1, Fees CP1, Holland WL1, Winger CC1, Batbayar K1, Ancar R1, Bergren T2, Petcoff D3, Stith BJ4.Author information 1University of Colorado Denver, Denver, CO 80217-3364, USA.2Community College of Aurora, CO, USA.3Metropolitan State University of Denver, CO, USA.4University of Colorado Denver, Denver, CO 80217-3364, USA. Electronic address: brad.stith@ucdenver.edu.AbstractWe report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC-γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca]i). Molecular species analysis and mass measurements suggested that sperm activate phospholipase D (PLD) to elevate phosphatidic acid (PA). We now report that PA mass increased 2.7 fold by 1min after insemination and inhibition of PA production by two methods inhibited activation of Src and PLCγ, increased [Ca]i and other fertilization events. As compared to 14 other lipids, PA specifically bound Xenopus Src but not PLCγ. Addition of synthetic PA activated egg Src (an action requiring intact lipid rafts) and PLCγ as well as doubling the amount of PLCγ in rafts. In the absence of elevated [Ca]i, PA addition elevated IP3 mass to levels equivalent to that induced by sperm (but twice that achieved by calcium ionophore). Finally, PA induced [Ca]i release that was blocked by an IP3 receptor inhibitor. As only PLD1b message was detected, and Western blotting did not detect PLD2, we suggest that sperm activate PLD1b to elevate PA which then binds to and activates Src leading to PLCγ stimulation, IP3 elevation and [Ca]i release. Due to these and other studies, PA may also play a role in membrane fusion events such as sperm-egg fusion, cortical granule exocytosis, the elevation of phosphatidylinositol 4,5-bisphosphate and the large, late increase in sn 1,2-diacylglycerol in fertilization.
• Developmental biology.Dev Biol.2013 Nov 21. pii: S0012-1606(13)00606-4. doi: 10.1016/j.ydbio.2013.11.006. [Epub ahead of print]
• We report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC-γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca]i). Molecular species analysis and mass meas
• PMID 24269904

• Long-chain polyunsaturated fatty acids (LCPUFA) from genesis to senescence: The influence of LCPUFA on neural development, aging, and neurodegeneration.

• Janssen CI1, Kiliaan AJ2.Author information 1Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Carola.Janssen@radboudumc.nl.2Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Amanda.Kiliaan@radboudumc.nl.AbstractMany clinical and animal studies demonstrate the importance of long-chain polyunsaturated fatty acids (LCPUFA) in neural development and neurodegeneration. This review will focus on involvement of LCPUFA from genesis to senescence. The LCPUFA docosahexaenoic acid and arachidonic acid are important components of neuronal membranes, while eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid also affect cardiovascular health and inflammation. In neural development, LCPUFA deficiency can lead to severe disorders like schizophrenia and attention deficit hyperactivity disorder. Perinatal LCPUFA supplementation demonstrated beneficial effects in neural development in humans and rodents resulting in improved cognition and sensorimotor integration. In normal aging, the effect of LCPUFA on prevention of cognitive impairment will be discussed. LCPUFA are important for neuronal membrane integrity and function, and also contribute in prevention of brain hypoperfusion. Cerebral perfusion can be compromised as result of obesity, cerebrovascular disease, hypertension, or diabetes mellitus type 2. Last, we will focus on the role of LCPUFA in most common neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. These disorders are characterized by impaired cognition and connectivity and both clinical and animal supplementation studies have shown the potential of LCPUFA to decrease neurodegeneration and inflammation. This review shows that LCPUFA are essential throughout life.
• Progress in lipid research.Prog Lipid Res.2013 Oct 24;53C:1-17. doi: 10.1016/j.plipres.2013.10.002. [Epub ahead of print]
• Many clinical and animal studies demonstrate the importance of long-chain polyunsaturated fatty acids (LCPUFA) in neural development and neurodegeneration. This review will focus on involvement of LCPUFA from genesis to senescence. The LCPUFA docosahexaenoic acid and arachidonic acid are important c
• PMID 24334113

Japanese Journal

• Metabolism and Synthesis of Lipids in the Polyunsaturated Fatty Acid-Producing Fungus Mortierella alliacea

• Jermsuntiea Worapol,Aki Tsunehiro,Kawamoto Seiji,Ono Kazuhisa
• Journal of Oleo Science 60(1), 11-17, 2011
• … Addition of linseed TAG to growing cultures resulted in a transient increase in extracellular 1,2-diacylglycerol (DAG), and even more so of 1,3-DAG, in the mycelia. … However, EPA production was not observed upon addition of ALA-rich 1,2- or 1,3-DAG, indicating that fatty acids released from exogenous lipids were used for resynthesis of mycelial TAG. …
• NAID 130000438321

• 38.ソテツとNostoc sp.の共生によるソテツ・サンゴ状根形成に関わるシグナル物質の検索(口頭発表)

• 田中 慎人,崎浜 靖子,橋床 泰之
• 植物化学調節学会研究発表記録集 (45), 55, 2010-10-01
• … Materials and Method) The coralloid roots collected at Yaku Island in late March, 2009 (1.08kg), and at Tanegashima Island, in early May, 2010 (6.25kg), were soaked in MeOH. … 1000ml) to be extracted with equal volume of EtOAc to give 2.58g of EtOAc solubles. … around the paper disc started to be dispersed within 2 days, the fraction was judged to contain HIF. …
• NAID 110007767138

Related Links

• Diacylglycerols, composition, structure, function, analysis

30 Nov 2011 ... sn-1,2-Diacylglycerols tend to be minor components of most tissues in quantitative terms, but they are very important in animal tissues ... Thus, sn-1,2- diacylglycerol is a key intermediate in the formation of phosphatidylcholine, ...

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1,2-diacylglycerol, DG, DAG

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　　[★] ジアシルグリセロール。DG DAG