Marmunti M, Catalá A
Cátedra de Bioquímica, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Argentina.
Int J Biochem Cell Biol. 1998 Sep;30(9):967-72. doi: 10.1016/s1357-2725(98)00043-0.
In the study reported here, the non-enzymatic (ascorbate-Fe2+) lipid peroxidation of rat liver nuclei and chromatin fractions was assayed. Chromatin obtained by sonication of nuclei suspended in 0.25 M sucrose was fractionated by differential sedimentation according to the following scheme: 3000, 12,000 and 27,500 g for 10 min each. The lowest density chromatin fraction was obtained by precipitation with cold ethanol of the supernatant obtained from the last centrifugation. Light emission = chemiluminescence, measured as cpm/mg protein, decreased in the order heavy > low density chromatin fractions during the peroxidation process. Analysis of fatty acids by gas chromatography showed that heavy density chromatin fractions are enriched with C20:4 n6 arachidonic acid, when compared with low density chromatin fractions. The amount of arachidonic acid C20:4 n6 was higher in repressed chromatin fractions as compared to the amount in the transcriptionally active chromatin which correlates with the level of lipid peroxidation.
在本文报道的研究中，对大鼠肝细胞核和染色质组分的非酶促（抗坏血酸 - 亚铁离子）脂质过氧化进行了测定。通过超声处理悬浮于0.25 M蔗糖中的细胞核所获得的染色质，按照以下方案通过差速沉降进行分级分离：每次在3000、12000和27500 g条件下离心10分钟。最低密度的染色质组分是通过用冷乙醇沉淀最后一次离心所得的上清液而获得的。在过氧化过程中，以每分钟计数/毫克蛋白质表示的发光（即化学发光）按照高密度>低密度染色质组分的顺序降低。气相色谱法分析脂肪酸表明，与低密度染色质组分相比，高密度染色质组分富含C20:4 n6花生四烯酸。与转录活性染色质中的含量相比，花生四烯酸C20:4 n6在抑制染色质组分中的含量更高，这与脂质过氧化水平相关。
