低密度脂蛋白的磷脂酶A2活性：载脂蛋白B-100存在内在磷脂酶A2活性的证据。
Phospholipase A2 activity of low density lipoprotein: evidence for an intrinsic phospholipase A2 activity of apoprotein B-100.
作者信息
Parthasarathy S, Barnett J
机构信息
Department of Medicine, University of California, San Diego, La Jolla 92093-0613.
出版信息
Proc Natl Acad Sci U S A. 1990 Dec;87(24):9741-5. doi: 10.1073/pnas.87.24.9741.
During oxidative modification of low density lipoprotein (LDL) there is extensive degradation of phosphatidylcholine (PtdCho) to lysophosphatidylcholine (lyso-PtdCho), with the removal of fatty acids from the 2 position. The phospholipase A2 (PLA2) activity responsible for hydrolysis is closely associated with LDL. By use of lipoxygenase-oxidized 2-[1-14C]linoleoyl PtdCho as the substrate and delipidated apoprotein B (apo-B), evidence is presented to show that (i) the activity is destroyed progressively during the oxidative modification of LDL; (ii) p-bromophenacyl bromide (pBPB), a histidine modifier that inhibits the oxidative modification of LDL, also substantially inhibits the PLA2 activity; and (iii) photooxidation of LDL in the presence of Rose Bengal completely inactivates the enzyme with concomitant loss of apo-B histidine residues. High molecular weight proteins from delipidated LDL, separated by polyacrylamide gel electrophoresis, showed PLA2 activity. It is suggested that apo-B itself may possess PLA2 activity.
在低密度脂蛋白（LDL）的氧化修饰过程中，磷脂酰胆碱（PtdCho）会大量降解为溶血磷脂酰胆碱（lyso-PtdCho），脂肪酸从2位被去除。负责水解的磷脂酶A2（PLA2）活性与LDL密切相关。通过使用脂氧合酶氧化的2-[1-14C]亚油酰PtdCho作为底物和脱脂载脂蛋白B（apo-B），有证据表明：（i）在LDL的氧化修饰过程中该活性逐渐被破坏；（ii）对溴苯甲酰溴（pBPB），一种抑制LDL氧化修饰的组氨酸修饰剂，也能显著抑制PLA2活性；（iii）在孟加拉玫瑰红存在下对LDL进行光氧化会使该酶完全失活，同时伴随apo-B组氨酸残基的丢失。通过聚丙烯酰胺凝胶电泳分离的脱脂LDL中的高分子量蛋白质显示出PLA2活性。提示apo-B本身可能具有PLA2活性。
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