Cholate solubilization of liver microsomal membrane components which promote NADPH-supported lipid peroxidation.
Cholate solubilization of liver microsomal membrane components which promote NADPH-supported lipid peroxidation.
复制标题
肝微粒体膜成分的胆酸盐溶解，促进 NADPH 支持的脂质过氧化。
DOI：
10.1016/0003-9861(92)90051-w
复制
发表时间：
1992
影响因子：
3.9
通讯作者：
Schenkman,JB
中科院分区：
文献类型：
--
作者：
Yonaha,M;Tampo,Y;Clarke,W;Davis,HW;Schenkman,JB
在焦磷酸铁存在下，肝微粒体中丙二醛(MDA)的产生受NADPH支持的脂质过氧化作用的监测，热处理或胰酶使其失活，加入纯化的NADPH-细胞色素P450还原酶(FPT)不能恢复其活性。微粒体中的胆酸钠对丙二醛有不同的增溶作用，在0.4%和1.2%胆酸钠之间溶解的部分被Sephadex G-150柱分离，并被分成A、B和C三个池。在焦磷酸铁和NADPH存在的情况下，通过将微体脂和FPT添加到柱上的特定部分来重组丙二醛的产生。B池在去除内源FPT后，对丙二醛的生成和花生四烯酸和二十二碳六烯酸的消失具有很高的催化活性，这种活性可被热处理和胰酶消化所消除，但不能被一氧化碳所消除。在含有Sephadex G-150柱组分的重组体系中，NADPH支持的脂质过氧化速率与细胞色素P450的含量无关。磷脂酶A2抑制剂对溴苯基溴可抑制NADPH支持的肝微粒体和重组体系中NADPH支持的脂质过氧化，但不能阻止铁-抗坏血酸或ABAP体系促进的微粒体脂质过氧化。另一种磷脂酶A2抑制剂，美帕林，对微粒体和Pool-B‘促进的脂质过氧化的抑制效果不佳，但确实阻止了抗坏血酸铁驱动的和ABAP促进的脂质过氧化。磷脂酶A2抑制剂氯丙嗪可作为自由基猝灭剂，阻止所有体系的脂质过氧化。所提供的数据与肝微体中存在一种促进脂质过氧化的不稳定蛋白因子是一致的，而不是FPT、细胞色素P450或磷脂酶A2。
NADPH-supported lipid peroxidation monitored by malondialdehyde (MDA) production in the presence of ferric pyrophosphate in liver microsomes was inactivated by heat treatment or by trypsin and the activity was not restored by the addition of purified NADPH-cytochrome P450 reductase (FPT). The activity was differentially solubilized by sodium cholate from microsomes, and the fraction solubilized between 0.4 and 1.2% sodium cholate was applied to a Sephadex G-150 column and sub fractionated into three pools, A, B, and C. MDA production was reconstituted by the addition of microsomal lipids and FPTto specific fractions from the column, in the presence of ferric pyrophosphate and NADPH. Pool B, after removal of endogenous FPT, was highly active in catalyzing MDA production and the disappearance of arachidonate and docosahexaenoate, and this activity was abolished by heat treatment and trypsin digestion, but not by carbon monoxide. The rate of NADPH-supported lipid peroxidation in the reconstituted system containing fractions pooled from Sephadex G-150 columns was not related to the content of cytochrome P450.p-Bromo-phenylacylbromide, a phospholipase A2inhibitor, inhibited NADPH-supported lipid peroxidation in both liver microsomes and the reconstituted system, but did not block the peroxidation of microsomal lipid promoted by iron-ascorbate or ABAP systems. Another phospholipase A2inhibitor, mepacrine, poorly inhibited both microsomal and pool-B′-promoted lipid peroxidation, but did block both iron-ascorbate-driven and ABAP-promoted lipid peroxidation. The phospholipase A2inhibitor chlorpromazine, which can serve as a free radical quencher, blocked lipid peroxidation in all systems. The data presented are consistent with the existence of a heat-labile protein-containing factor in liver microsomes which promotes lipid peroxidation and is not FPT, cytochrome P450, or phospholipase A2.