Abdelkarim Abousalham

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The mechanism of inhibition of phospholipase D (PLD) by ceramides was determined using granulocytes differentiated from human promyelocytic leukemic (HL-60) cells. In a cell-free system, hydrolysis of phosphatidylcholine by membrane-bound PLD depended upon phosphatidylinositol 4,5-bisphosphate, guanosine 5'-3-O-(thio)triphosphate) (GTPgammaS), and cytosolic(More)
Glucose metabolism in pancreatic β cells stimulates insulin granule exocytosis, and this process requires generation of a lipid signal. However, the signals involved in lipid amplification of glucose-stimulated insulin secretion (GSIS) are unknown. Here we show that in β cells, glucose stimulates production of lipolysis-derived long-chain saturated(More)
Egg yolk emulsions containing phospholipids (about 31%, w/w) are classically used as substrates for measuring phospholipase A2 activity using the pH-stat method. Here we investigated the susceptibility of egg yolk lipoproteins to lipolysis by various highly purified lipases of animal or microbial origin. Egg yolk lipoproteins, which contain up to 65%(More)
The present review aims to systematically and critically analyze the current knowledge on phospholipases and their role in physiological and pathological mineralization undertaken by mineralization competent cells. Cellular lipid metabolism plays an important role in biological mineralization. The physiological mechanisms of mineralization are likely to(More)
We have studied the kinetics of hydrolysis of triacylglycerols, vinyl esters and p-nitrophenyl butyrate by four carboxylesterases of the HSL family, namely recombinant human hormone-sensitive lipase (HSL), EST2 from Alicyclobacillus acidocaldarius, AFEST from Archeoglobus fulgidus, and protein RV1399C from Mycobacterium tuberculosis. The kinetic properties(More)
The fatty acid specificity of phospholipase D purified from germinating sunflower seeds was studied using mixed micelles with variable detergent/phospholipid ratios. The main advantage of this approach is that since the substrate is integrated in the detergent micelles, comparisons can be made between the kinetic constants of a wide range of(More)
Differential effects of acetyl(C2-) ceramide (N-acetylsphingosine) were studied on coated vesicle formation from Golgi-enriched membranes of Chinese hamster ovary (CHO) and Madin-Darby canine kidney (MDCK) cells. C2-ceramide blocked the translocation of ADP-ribosylation factor-1 (ARF-1) and protein kinase C-alpha (PKC-alpha) to the membranes from CHO cells,(More)
Phospholipase D (phosphatidylcholine phosphatidohydrolase EC 3.1.4.4) from soybean (Glycine max L.) suspension-cultured cell was purified around 1,200-fold to homogeneity by acetone precipitation, Macro-Prep High Q anion exchange, and octyl-Sepharose CL-4B affinity chromatography. The purified enzyme released 1,600 mumol of choline per min per mg of(More)
Phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4) was purified from cabbage leaves. The two step purification procedure involved hydrophobic chromatography on Octyl-Sepharose followed by a Mono-Q/FPLC-column with a total yield of 23% and a purification factor of 1000. A zymographic assay was used to detection of PL D activities at(More)
Phospholipase D (PLD) is an important enzyme involved in signal transduction, vesicle trafficking and membrane metabolism. In this study, large amounts of a recombinant plant PLD alpha were secreted into the culture medium of baculovirus-infected insect cells and purified to homogeneity in the form of a fully active enzyme. The transient production of(More)