The effects of steroid hormones, glucagon and insulin on rat liver phosphatidate phosphohydrolase (PAP) activity were studied both in vitro and in vivo. Incubation of rat hepatocytes with each hormone showed that dehydroepiandrosterone (DHEA), progesterone and testosterone increase PAP activity by 44.6, 37 and 36.9%, respectively. Estradiol, however, decreased enzyme activity by 13.6% under...

Pectin is known as a cholesterol-reducing dietary fibre, and in the present study we addressed the question whether pectin affected the quantity of lipid in droplets in the myocardial cells and of lipid in the liver cells. Male Wistar rats received either a diet containing cholesterol or a standard diet without cholesterol with 0, 50 or 100 g pectin/kg incorporated for 10 d. The fractional volu...

In the present study we have characterized mammalian sphingosine-1-phosphate phosphohydrolase (SPP1), an enzyme that specifically dephosphorylates sphingosine 1-phosphate (S1P) and which differs from previously described lipid phosphate phosphohydrolases. Based on sequence homology to murine SPP1, we cloned the human homolog. Transfection of human embryonic kidney 293 and Chinese hamster ovary ...

phosphatidate phosphohydrolase (pap) from cytosolic fraction of rat liver was purified to homogeneity having specific activity of 5.14 u/mg protein. an activity staining procedure was developed to determine molecular weight of the enzyme on polyacrylamide gel electrophoresis using ferguson plot. molecular weight (m.w.) of the active pap was 298 kda. sds-page analysis showed a m.w. of 47 kda for...

BACKGROUND Phosphatidic acid phosphatase (PAP, EC 3.1.3.4) catalyzes the dephosphorylation of phosphatidate yielding diacylglycerol (DAG), the lipid precursor for triacylglycerol (TAG) biosynthesis. Despite the importance of PAP activity in TAG producing bacteria, studies to establish its role in lipid metabolism have been so far restricted only to eukaryotes. Considering the increasing interes...

Changes in nuclear size and shape during the cell cycle or during development require coordinated nuclear membrane remodeling, but the underlying molecular events are largely unknown. We have shown previously that the activity of the conserved phosphatidate phosphatase Pah1p/Smp2p regulates nuclear structure in yeast by controlling phospholipid synthesis and membrane biogenesis at the nuclear e...

Phosphatidate-dependent protein phosphorylation was observed in soluble extracts from rat liver, brain, lung, and testis. The phosphorylation was stimulated by free Ca2+ in the range of 360-800 nM. Incubation mixtures containing phosphatidate provided markedly different profiles of protein phosphorylation from those with phosphatidylserine plus 1,2-diolein. Phosphatidate-dependent phosphorylati...