Arnhold J, Wiegel D, Richter O, Hammerschmidt S, Arnold K, Krumbiegel M
Institute of Biophysics, School of Medicine, University of Leipzig, Germany.
Biomed Biochim Acta. 1991;50(8):967-73.
Human low density lipoproteins (LDL) were incubated with increasing amounts of sodium hypochlorite. A decrease of the number of free amino groups on the LDL surface starts only upon addition of 30-40 moles NaOCl per mole apoB, whereas all detectable SH groups are oxidized after addition of nearly 17-20 moles NaOCl. All hypochlorite-modified LDL samples have a higher electronegative surface charge compared with native LDL as revealed by agarose gel electrophoresis and partition of LDL in an aqueous polyethylene glycol/dextran two-phase system. The more NaOCl is used to alter LDL, the higher is the electrical surface charge. Changes in surface charge are found already at low NaOCl concentrations where no decrease of amino groups is detected. It is assumed that changes in surface charge are caused by the formation of monochloramines and especially at low degrees of modification by a further unknown contribution. An effect on the primary structure of apoB or peroxidation-like changes in NaOCl-altered LDL could not be found under our experimental conditions. The results are discussed with respect to such modifications under in vivo conditions by hypochlorous acid generated in stimulated phagocytosing cells.
将人低密度脂蛋白（LDL）与不断增加量的次氯酸钠一起孵育。仅在每摩尔载脂蛋白B添加30 - 40摩尔次氯酸钠时，LDL表面游离氨基的数量才开始减少，而在添加近17 - 20摩尔次氯酸钠后，所有可检测到的巯基都被氧化。如琼脂糖凝胶电泳以及LDL在聚乙二醇/葡聚糖水相两相系统中的分配所示，与天然LDL相比，所有经次氯酸盐修饰的LDL样品都具有更高的负电表面电荷。用于改变LDL的次氯酸钠越多，表面电荷就越高。在未检测到氨基减少的低次氯酸钠浓度下就已发现表面电荷的变化。据推测，表面电荷的变化是由一氯胺的形成引起的，尤其是在低修饰程度时还有未知的进一步作用。在我们的实验条件下，未发现次氯酸钠改变的LDL对载脂蛋白B的一级结构或类似过氧化的变化有影响。结合在受刺激的吞噬细胞中产生的次氯酸在体内条件下进行的此类修饰，对结果进行了讨论。
