Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901.
Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901.
J Lipid Res. 2012 Mar;53(3):522-528. doi: 10.1194/jlr.M022798. Epub 2011 Dec 16.
Phosphatidate (PA) phosphatase, the enzyme that catalyzes the penultimate step in triacylglycerol synthesis, is a cytosolic enzyme that must associate with the membrane where its substrate PA resides. Fluorescence spectroscopy was used to measure the interaction of yeast PAH1-encoded PA phosphatase with model liposome membranes. PA phosphatase contains five tryptophan residues and exhibited inherit fluorescence that increased upon interaction with phosphatidylcholine liposomes. The interaction was enhanced by inclusion of other phospholipids and especially the substrate PA. Interaction was dependent on both the concentration of phosphatidylcholine-PA liposomes as well as the surface concentration of PA in liposomes. Mg(2+) ions, which were required for catalysis, did not affect PA phosphatase interaction with phosphatidylcholine-PA liposomes. PA phosphatase was a substrate for protein kinase A, protein kinase C, and casein kinase II, and these phosphorylations decreased PA phosphatase interaction with phosphatidylcholine-PA liposome membranes.
磷酸酶，催化三酰甘油合成倒数第二步的酶，是一种细胞质酶，必须与含有其底物 PA 的膜结合。荧光光谱法用于测量酵母 PAH1 编码的磷酸酶与模型脂囊泡膜的相互作用。磷酸酶含有五个色氨酸残基，与磷脂酰胆碱脂囊泡相互作用时会增加固有荧光。与其他磷脂的相互作用增强，特别是底物 PA。相互作用既依赖于含有 PA 的磷酸胆碱脂囊泡的浓度，也依赖于脂囊泡中 PA 的表面浓度。催化所需的 Mg(2+) 离子不影响磷酸酶与磷酸胆碱-PA 脂囊泡的相互作用。磷酸酶是蛋白激酶 A、蛋白激酶 C 和酪蛋白激酶 II 的底物，这些磷酸化作用降低了磷酸酶与磷酸胆碱-PA 脂囊泡膜的相互作用。
