Butterwith S C, Martin A, Brindley D N
Biochem J. 1984 Sep 1;222(2):487-93. doi: 10.1042/bj2220487.
Incubating the particle-free supernatant of rat liver with alkaline phosphatase decreased the activity of phosphatidate phosphohydrolase by 21-29%. When the particle-free supernatant was incubated with various combinations of Mg2+, ATP, cyclic AMP and cyclic AMP-dependent protein kinase this failed to alter significantly phosphatidate phosphohydrolase activity under the conditions employed. The incubation of hepatocytes in monolayer culture with 0.5 mM-8-(4-chlorophenylthio)adenosine 3',5'-monophosphate increased the total activity of phosphatidate phosphohydrolase as measured in vitro. This also decreased the proportion of the phosphohydrolase that was associated with the membrane fraction of the cells and increased that in the cytosolic fraction. Adding 1 mM-oleate to the hepatocytes promoted the translocation of phosphatidate phosphohydrolase from the cytosol to the membrane-associated compartment. Oleate overcame the effect of the cyclic AMP analogue in favouring the cytosolic distribution of the phosphohydrolase. These results are discussed in relation to the interaction of hormonal balance and substrate supply in controlling the synthesis of phosphatidylcholine and triacylglycerol in the liver in stress and in diabetes. It is proposed that the cytosolic phosphatidate phosphohydrolase activity represents a reservoir of potential activity that becomes expressed when the enzyme translocates to the membranes on which the synthesis of glycerolipids occurs.
用碱性磷酸酶孵育大鼠肝脏的无颗粒上清液，会使磷脂酸磷酸水解酶的活性降低21% - 29%。当用Mg2+、ATP、环磷酸腺苷和环磷酸腺苷依赖性蛋白激酶的各种组合孵育无颗粒上清液时，在所采用的条件下，这并未显著改变磷脂酸磷酸水解酶的活性。用0.5 mM - 8 -（4 - 氯苯基硫代）腺苷3'，5'-单磷酸孵育单层培养的肝细胞，会增加体外测定的磷脂酸磷酸水解酶的总活性。这也降低了与细胞的膜部分相关的磷酸水解酶的比例，并增加了胞质部分的比例。向肝细胞中添加1 mM油酸会促进磷脂酸磷酸水解酶从胞质溶胶向膜相关区室的转运。油酸克服了环磷酸腺苷类似物有利于磷酸水解酶胞质分布的作用。结合应激和糖尿病状态下肝脏中激素平衡与底物供应在控制磷脂酰胆碱和三酰甘油合成中的相互作用，对这些结果进行了讨论。有人提出，胞质磷脂酸磷酸水解酶活性代表了一种潜在活性储备，当该酶转运到发生甘油olipids合成的膜上时就会表现出来。
