the effect of epinephrine on phosphatidate phosphohydrolase (pap) activity of isolated human hepatocytes was studied. epineprine inhibited the enzyme activity progressively at concentrations above 0.1 µm, reaching a maximum inhibition of 64.5% at 100 µm concentration. inclusion of alprenolol, a β-receptor blocker, in the incubation mixture abolished the inhibitory effect of epinephrine on pap, ...

Phosphatidate bilayers composed of dilauroylphosphatidate, dimyristoylphosphatidate, dipalmitoylphosphatidate and dioleoylphosphatidate were prepared. Their interaction with AMP deaminase isolated from pig heart was investigated. Dioleoylphosphatidate bilayers were found to exert non-competitive inhibition on the AMP deaminase with a Ki of 15 x 10(-6) M. This inhibition is three orders of magni...

For a purified preparation of the soluble form of phosphatidate phosphohydrolase (EC 3.1.3.4) from guinea pig cerebral cortex, I-O-alkyl-racglycerol 3-phosphate was found to be accepted as a substrate. This substrate analog was tritium-labeled in order to serve in a rapid sensitive assay for the enzyme, in which labeled I-alkyl glycerol is released. Heat denaturation and enzyme activity depende...

A sensitive radioactive assay of acyl CoA:sn-glycerol3-phosphate-0-acyltransferase (EC 2.3.1.15) was developed to study the properties and subcellular distribution of this enzyme in rat epididymal adipose tissue. The esterification of sn-glycerol-3-phosphate was measured in the presence of palmitoyl CoA or palmitate, ATP, CoA, and Mg2+ at pH 7.5. The presence of glycerophosphate acyltransferase...

Phosphatidic acid is synthesized by a particulate preparation of of guinea pig liver from dihydroxyacetone phosphate, acyl CoAs and NADPH via acyl dihydroxyacetone phosphate. Glycerol-3-phosphate is also converted to phosphatidate in this system. The phosphatidate formed via acyl dihydroxyacetone phosphate has more saturated fatty acid in the lposition than in the Z-position, while the fatty ac...

Yeast Pah1p phosphatidate phosphatase (PAP) catalyzes the penultimate step in the synthesis of triacylglycerol. PAP plays a crucial role in lipid homeostasis by controlling the relative proportions of its substrate phosphatidate and its product diacylglycerol. The cellular amounts of these lipid intermediates influence the synthesis of triacylglycerol and the pathways by which membrane phosphol...

phosphatidate phosphohydrolase (pap2b, fraction b) was purified from the plasma membrane ofrat liver cells. the km for the surface concentration of phosphatidic acid was 0.43 mol%. the subunit of theenzyme had an m.w. of 33.8 kda using sodium dodecyl sulfate polyacrylamide gel electrophoresis. thenative enzyme shows a molecular weight of 182 kda in a gel filtration column packed with sephacryl ...

BACKGROUND Proteins in the lipin family play a key role in lipid synthesis due to their phosphatidate phosphatase activity, and they also act as transcriptional coactivators to regulate the expression of genes involved in lipid metabolism. The lipin family includes three members, lipin1, lipin2, and lipin3, which exhibit tissue-specific expression, indicating that they may have distinct roles i...