Lipid peroxide formation in microsomes. The role of non-haem iron.
Lipid peroxide formation in microsomes. The role of non-haem iron.
复制标题
微粒体中脂质过氧化物的形成。
作者：
E. Wills
1. 金属离子螯合剂，如EDTA，邻菲罗啉或去铁胺，当用纯蔗糖制备的匀浆制备的大鼠肝微粒体与抗坏血酸或NADPH孵育时，抑制脂质过氧化形成。2. 用金属离子螯合剂处理的微粒体在孵育过程中不会形成过氧化物，除非随后加入低浓度的无机铁（Fe（2+）或Fe(3+)）。没有其他金属离子能充分取代无机铁。3. 由含有EDTA （1mm）的蔗糖匀浆制备的微粒体在与抗坏血酸盐或NADPH孵育时不会形成过氧化脂质，除非添加铁（2+）。制备后用蔗糖清洗微粒体可恢复大部分形成过氧化脂质的能力。4. 由蔗糖制备的微粒体中的脂质过氧化形成在小程度上受到无机铁的刺激，但如果加入含有铁化合物作为污染物的腺嘌呤核苷酸，则会在更大程度上受到刺激。5. 正常微粒体制剂中含有的铁以血红素和非血红素的形式存在。一种非血红素成分，其中铁可能与磷酸盐相连，被认为对抗坏血酸系统和NADPH系统都是必需的，这些系统催化微粒体中的脂质过氧化。
1. Metal ion-chelating agents such as EDTA, o-phenanthroline or desferrioxamine inhibit lipid peroxide formation when rat liver microsomes prepared from homogenates made in pure sucrose are incubated with ascorbate or NADPH. 2. Microsomes treated with metal ion-chelating agents do not form peroxide on incubation unless inorganic iron (Fe(2+) or Fe(3+)) in a low concentration is added subsequently. No other metal ion can replace inorganic iron adequately. 3. Microsomes prepared from sucrose homogenates containing EDTA (1mm) do not form lipid peroxide on incubation with ascorbate or NADPH unless Fe(2+) is added. Washing the microsomes with sucrose after preparation restores most of the capacity to form lipid peroxide. 4. Lipid peroxide formation in microsomes prepared from sucrose is stimulated to a small extent by inorganic iron but to a greater extent if adenine nucleotides, containing iron compounds as a contaminant, are added. 5. The iron contained in normal microsome preparations exists in haem and in non-haem forms. One non-haem component in which the iron may be linked to phosphate is considered to be essential for both the ascorbate system and NADPH system that catalyse lipid peroxidation in microsomes.