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Biochemical and Biophysical Research... Aug 2012
Topics: Animals; Calcium; Cations, Divalent; Diglycerides; Enzyme Activation; History, 20th Century; Protein Kinase C; Rats
PubMed: 22925676
DOI: 10.1016/j.bbrc.2012.08.026 -
The Journal of Biological Chemistry May 1986Diacylglycerol kinase is though to play a central role in the metabolism of diacylglycerol second messengers in agonist-stimulated cells. A series of diacylglycerol...
Diacylglycerol kinase is though to play a central role in the metabolism of diacylglycerol second messengers in agonist-stimulated cells. A series of diacylglycerol analogs were tested for their ability to act as substrates or inhibitors of diacylglycerol kinase with the goal of determining the substrate specificity of the enzyme, and of discovering inhibitors. Screening of these compounds was performed using a partially purified diacylglycerol kinase from pig brain. Modified assays for this enzyme using co-sonicated mixtures of diacylglycerol and anionic phospholipids were developed. This enzyme was found to be quite specific for sn-1,2-diacylglycerol (KM 24 microM for dioctanoyl-glycerol). Among the analogs investigated, only 1,2-dioctanoyl-2-amino-1,3-propanediol was utilized at a significant rate. Two analogs, dioctanoylethylene glycol (KI 58 microM) and 1-monooleoylglycerol (KI 91 microM), were potent inhibitors in vitro. These compounds were tested for effects on diacylglycerol formation and metabolism in thrombin-stimulated human platelets. Dioctanoylethylene glycol inhibited diacylglycerol phosphorylation in platelets (70-100% at 100 microM) leading to a longer-lived diacylglycerol signal. This compound may be a useful tool for studies of diacylglycerol kinase in other cell types. 1-Monooleoylglycerol treatment elevated diacylglycerol levels up to 4-fold in unstimulated platelets and up to 10-fold in thrombin-stimulated platelets. The implications with regard to the pathways of diacylglycerol metabolism in human platelets are discussed.
Topics: Blood Platelets; Diacylglycerol Kinase; Diglycerides; Glycerides; Humans; Kinetics; Phospholipids; Phosphotransferases; Structure-Activity Relationship; Substrate Specificity
PubMed: 3009483
DOI: No ID Found -
Trends in Endocrinology and Metabolism:... Sep 2019Skeletal muscle (SM) insulin resistance (IR) plays an important role in the burden of obesity, particularly because it leads to glucose intolerance and type 2 diabetes.... (Review)
Review
Skeletal muscle (SM) insulin resistance (IR) plays an important role in the burden of obesity, particularly because it leads to glucose intolerance and type 2 diabetes. Among the mechanisms thought to link IR to obesity is the accumulation, in muscle cells, of different lipid metabolites. Diacylglycerols (DAGs) are subject of particular attention due to reported interactions with the insulin signaling cascade. Given that SM accounts for the majority of insulin-stimulated glucose uptake, this review integrates recent observational and mechanistic works with the sole focus on questioning the role of DAGs in SM IR. Particular attention is given to the subcellular distributions and specific structures of DAGs, highlighting future research directions towards reaching a consensus on the mechanistic role played by DAGs.
Topics: Animals; Diglycerides; Humans; Insulin Resistance; Lipid Metabolism; Muscle, Skeletal
PubMed: 31375395
DOI: 10.1016/j.tem.2019.06.005 -
Clinica Chimica Acta; International... Jan 1995A method for the analysis of 1,2-diacylglycerols in biological samples is presented. After tissue extraction and derivatisation with 3,5-dinitrobenzoyl chloride, samples...
A method for the analysis of 1,2-diacylglycerols in biological samples is presented. After tissue extraction and derivatisation with 3,5-dinitrobenzoyl chloride, samples are analysed by normal phase HPLC, using a 3.9 x 300 mm microPorasil column, and ultraviolet detection at 254 nm. The method gives quantitative recovery of 1,2-diacylglycerol, and is of sufficient sensitivity to allow quantitation of 1,2-diacylglycerol in human muscle needle biopsy specimens, from as little as 10 mg muscle. Human skeletal muscle from fasted control subjects was found to have a 1,2-diacylglycerol content of 455 +/- 78 nmol/g wet weight. The method is robust, giving intra- and inter-assay coefficients of variation of 2.9% and 5.9%, respectively, and should prove useful for the analysis of 1,2-diacylglycerol levels in human disease states, such as diabetes, in which no measurements of 1,2-diacylglycerol have yet been undertaken.
Topics: Animals; Chromatography, High Pressure Liquid; Diglycerides; Humans; Male; Muscle, Skeletal; Rats; Rats, Wistar; Spectrophotometry, Ultraviolet
PubMed: 7758224
DOI: 10.1016/0009-8981(94)05799-x -
Biochimica Et Biophysica Acta Oct 1997For many of the enzymes that utilize or produce diacylglycerols, detergent mixed micelles are often used in assay systems to solubilize the lipophilic substrates or...
For many of the enzymes that utilize or produce diacylglycerols, detergent mixed micelles are often used in assay systems to solubilize the lipophilic substrates or products. The assumption is often made that the diacylglycerol (DAG) is solubilized and well mixed throughout the population of micelles during the time course of the assay. In the present work the partitioning and exchange dynamics of diacylglycerols (from dihexanoyl-DAG to didecanoyl-DAG) in a variety of detergent micelles have been studied by NMR and fluorescence methods. In all detergents, the longer the DAG chain lengths, the more detergent is required for solubilization. However, efficiency of solubilization varies tremendously with Triton X-100 the most efficient (i.e. the least detergent is required), and deoxycholate the least efficient in solubilizing DAG. The mixing and exchange dynamics of pyrene-labeled DAG molecules in these micelles (measured by stopped-flow fluorescence) were fastest for Triton X-100 and slowest with charged bile salt micelles. Of the detergent systems characterized, Triton X-100 appears to be the optimal detergent for use in assays of enzymes that interact with DAG (beta-octylglucoside and diheptanoylphosphatidylcholine have good exchange dynamics, but higher amounts of these detergents are needed to solubilize DAG). Bile salt micelles provide the least solubilization and the slowest exchange kinetics (so slow that this could be a significant problem in some enzyme assays). This information on DAG behavior in micelles is discussed with respect to assays of an enzyme that generates DAG as product (phospholipase C) and one that uses DAG as substrate (DAG kinase). Although slow exchange of DAG occurs in some micelle systems, this does not appear to be a rate-limiting step in the kinetics for either of these enzymes.
Topics: Bacillus cereus; Detergents; Diacylglycerol Kinase; Diglycerides; Escherichia coli; Glucosides; Kinetics; Magnetic Resonance Spectroscopy; Micelles; Molecular Conformation; Octoxynol; Solubility; Type C Phospholipases
PubMed: 9366244
DOI: 10.1016/s0005-2760(97)00066-0 -
Biophysical Journal Oct 2003We have studied the effect of phospholipase C from Bacillus cereus and Clostridium perfringens (alpha-toxin) on giant stearoyl-oleoyl phosphatidylcholine (SOPC)...
We have studied the effect of phospholipase C from Bacillus cereus and Clostridium perfringens (alpha-toxin) on giant stearoyl-oleoyl phosphatidylcholine (SOPC) vesicles. Enzyme activity leads to a binary mixture of SOPC and the diacylglycerol SOG, which phase separates into a SOPC-rich bilayer phase and a SOG-rich isotropic bulk-like domain embedded within the membrane, as seen directly by phase contrast microscopy. After prolonged enzymatic attack, all bilayer membranes are transformed into an isotropic pure SOG phase as characterized by fluorescence microscopy, differential scanning calorimetry, fluorescence anisotropy measurements, and small angle x-ray scattering. These domains may have biological relevance, serving as storage compartments for hydrophobic molecules and/or catalyzing cellular signaling events at their boundaries. Furthermore, in the early stages of asymmetric enzymatic attack to the external monolayer of giant vesicles, we observe a transient coupling of the second-messenger diacylglycerol to membrane spontaneous curvature, which decreases due to enzyme activity, before domain formation and final vesicle collapse occurs.
Topics: Diglycerides; Lipid Bilayers; Liposomes; Membrane Fluidity; Membrane Microdomains; Membranes, Artificial; Phosphatidylcholines; Surface Properties; Type C Phospholipases
PubMed: 14507699
DOI: 10.1016/S0006-3495(03)74659-1 -
Food Research International (Ottawa,... Jun 2019Diacylglycerols (DAGs) are interesting oil structuring molecules as they are structurally similar to triacylglycerols (TAGs), but are metabolized differently which...
Diacylglycerols (DAGs) are interesting oil structuring molecules as they are structurally similar to triacylglycerols (TAGs), but are metabolized differently which results in weight loss and improved blood cholesterol levels upon dietary replacement of TAGs with DAGs. Many commercial products consist of a mixture of monoacylglycerols (MAGs) and DAGs, yet the effect of MAGs on the crystallization behavior of DAGs is still to be unraveled. Two types of commercial MAGs, one originating from hydrogenated palm stearin and one of hydrogenated rapeseed oil, were added in concentrations 1, 2 and 4% to 20% DAGs derived from hydrogenated soybean oil. Using differential scanning calorimetry, it was shown that the presence of MAGs delayed the onset of DAG crystallization. Rheological analysis revealed that MAGs also hindered crystal network development. Synchrotron X-ray diffraction analysis demonstrated that the addition of MAGs suppressed the formation of the β form and stimulated the development of the β' form. Likely, MAGs mainly hindered the crystallization of 1,3-DAGs, which are responsible for the development of the β form, and stimulated the crystallization of the 1,2-DAGs, which can crystallize in the α and β' forms. The presence of two polymorphic forms resulted in a decrease of the crystal network strength, as was derived from oscillatory rheological measurements. This research implies a different effect of monoacylglycerols on both the nucleation and crystal growth of 1,2- and 1,3-DAG isomers. This insight is not only relevant for oleogelation research, but also for emulsifying agents which often contain blends of MAGs, 1,2-DAGs and 1,3-DAGs.
Topics: Calorimetry, Differential Scanning; Crystallization; Diglycerides; Monoglycerides; Plant Oils; Rheology; X-Ray Diffraction
PubMed: 31000265
DOI: 10.1016/j.foodres.2018.10.092 -
Journal of Separation Science Dec 2018Unlike the synthetic surfactants, mono- and diacylglycerols have the advantage to be biodegradable and non-toxic. In the present work, the hydrolysis of lipid fraction...
Unlike the synthetic surfactants, mono- and diacylglycerols have the advantage to be biodegradable and non-toxic. In the present work, the hydrolysis of lipid fraction by-products of refined vegetable oils was performed by Serratia sp. W lipase immobilized on CaCO by combined adsorption and precipitation. This support was selected out of four carriers as it exhibited the finest activity support (950 U/g) and the most satisfactory behavior at use. The immobilized preparation with CaCO was stable and active in the whole range of pH (4 to 9) and temperature (37 to 55°C), yielding a 75% degree of hydrolysis at optimal environmental conditions of pH 8.5 and temperature 55°C. Thin-layer chromatography, gas chromatography, and liquid chromatography methods were evaluated to determine the analytical characterization of hydrolysis products. For monoacylglycerols and diacylglycerol fractions identified in the samples, a novel approach by liquid chromatography method was employed, through a homemade linear retention index database and a dedicated software. The adopted approach allowed the use of basic instrumentation set-ups, without the need of sophisticated detectors, such as mass spectrometers. Thus, it could be an effective alternative to produce emulsifiers from cheap vegetable oils.
Topics: Adsorption; Calcium Carbonate; Diglycerides; Enzymes, Immobilized; Hydrogen-Ion Concentration; Hydrolysis; Lipase; Monoglycerides; Particle Size; Plant Oils; Serratia; Software; Surface Properties; Temperature; Vegetable Products
PubMed: 30281203
DOI: 10.1002/jssc.201800432 -
Lipids Dec 2010Diacylglycerol (DAG) supplementation has been shown to be associated with the reduction of fasting serum triacylglycerol (TAG) concentration, although the extent of the... (Meta-Analysis)
Meta-Analysis
Diacylglycerol (DAG) supplementation has been shown to be associated with the reduction of fasting serum triacylglycerol (TAG) concentration, although the extent of the association is uncertain. We quantitatively examined the effect of dietary DAG on fasting serum TAG concentration by conducting a meta-analysis of randomized controlled trials. Potential papers were searched from electronic databases of Medline, Embase and Cochrane Library. Information was extracted and the net change of fasting serum TAG concentration was used as the primary outcome to examine the effect of DAG in Review Manager 4.2. Six papers with seven independent studies (298 subjects) were included into the statistic pooling. Meta-analysis with random effect model showed that DAG did not reduce the fasting serum TAG concentration (WMD: -0.07 mmol/L; 95% CI: -0.21 to 0.08 mmol/L; P = 0.37). Sensitivity analysis indicated the robustness of overall results. Fail-safe number analysis indicated that 18 studies with positive effect were necessary to reverse the reported non-significant efficacy of DAG. Weight estimation analysis indicated that the effect of DAG was influenced to some extent by the initial fasting serum TAG concentration. In conclusion, DAG supplementation did not reduce the fasting serum TAG concentration significantly compared with TAG, but some effects were suggested in diabetic patients with hypertriglyceridemia.
Topics: Adult; Diglycerides; Fasting; Humans; Hypertriglyceridemia; Middle Aged; Triglycerides; United States
PubMed: 21104449
DOI: 10.1007/s11745-010-3478-0 -
QJM : Monthly Journal of the... Apr 2007
Topics: Adult; Diglycerides; Humans; Hyperlipoproteinemia Type I; Male
PubMed: 17434913
DOI: 10.1093/qjmed/hcm018