Isolation of a cytochrome b 6 -f particle from chloroplasts.
Isolation of a cytochrome b 6 -f particle from chloroplasts.
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从叶绿体中分离细胞色素 b 6 -f 颗粒。
DOI：
10.1016/s0021-9258(19)45547-6
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发表时间：
1972
期刊：
影响因子：
--
通讯作者：
J. Neumann
中科院分区：
文献类型：
--
作者：
N. Nelson;J. Neumann
如前所述（纳尔逊，N.，Dreschler，Z.，和Neumann，J.（1970）J.Biol.Chem.245，143），但使用更高的去污剂浓度。通过加入硫酸鱼精蛋白并离心，从系统1颗粒中分离细胞色素b 6-f颗粒。通过Bio-Gel和DEAE-柱层析和硫酸铵沉淀来纯化颗粒。纯化过程中需要加入去污剂以防止细胞色素的聚集，纯化后的颗粒中细胞色素b 6与细胞色素m的比值接近2，含有非血红素铁和磷脂。它不含叶绿素，但含有胡萝卜素。计算的颗粒的最小分子量为103，000每1血红素c。通过测量吡啶血色络合物的吸光度来确定颗粒中细胞色素的摩尔消光系数。对于细胞色素b 6，获得的摩尔消光系数如下：在563 nm-575 nm处还原-氧化，24，400;在563 nm-542 nm处，20，700。对细胞色素f，在554 - 538 nm处，还原-氧化的摩尔消光系数为20，600;并且在554 nm减去565 nm 23处，细胞色素b 6-f颗粒的E_0为+330毫伏，细胞色素b 6-f颗粒的E_0为-100毫伏，与细胞色素b-c_1复合体的E_0相似（复合物III）从线粒体。目前的研究结果的光合电子传递途径的操作的一些影响进行了讨论。
System 1 particles were prepared from lettuce chloroplasts by the addition of digitonin and differential centrifugation as described previously (Nelson, N., Dreschler, Z., and Neumann, J. (1970)J. Biol. Chem.245, 143), but higher detergent concentrations were used. A cytochromeb6-fparticle was isolated from System 1 particles by the addition of protamine sulfate and centrifugation. The particle was purified by Bio-Gel and DEAE-column chromatography and ammonium sulfate precipitation. The presence of detergents during purification was required in order to prevent aggregation of the cytochromes.The ratio of cytochromeb6to cytochromefin the purified particle was close to 2.The particle contained non-heme iron and phospholipids. It was devoid of chlorophyll but contained carotenes. The calculated minimum molecular weight of the particle was 103,000 per 1 heme c.The molar extinction coefficient of the cytochromes in the particle was determined by measuring the absorbance of the pyridine hemochrome complexes. For cytochromeb6the molar extinction coefficients obtained were as follows: reduced minus oxidized at 563 nm minus 575 nm, 24,400; and at 563 nm minus 542 nm, 20,700. For cytochromefthe molar extinction coefficients obtained were as follows: reduced minus oxidized at 554 nm minus 538 nm, 20,600; and at 554 nm minus 565 nm 23,000.The E0of cytochromefin the particle is +330 mvolts and that of cytochromeb6is -100 mvolts.The cytochromeb6-fparticle from chloroplasts shows similarities with the cytochromeb-c1complex (Complex III) from mitochondria.Some implications of the present findings for the operation of photosynthetic electron transport pathways are discussed.