Bearden A J, Malkin R
Biochim Biophys Acta. 1976 Jun 8;430(3):538-47. doi: 10.1016/0005-2728(76)90029-3.
The extent of P-700 photooxidation at 18 degrees K has been followed in three different chloroplast preparations (unfractionated chloroplasts and two preparations enriched in Photosystem I). More than 90% of P-700+ formation in all preparations was eliminated by the addition of sodium dithionite at pH 10. Photoreduction of a bound chloroplast iron-sulfur protein was also decreased by at least 90% under similar conditions. Electron paramagnetic resonance spectra of the chloroplast preparations in the presence of dithionite showed chemical reduction of bound iron-sulfur protein under conditions where primary photochemistry is eliminated. These results indicate that P-700 photooxidation is concomitant with photoreduction of a bound iron-sulfur protein and that this iron-sulfur protein functions as the primary electron acceptor of Photosystem I.
在18K下，对三种不同的叶绿体制剂（未分级的叶绿体和两种富含光系统I的制剂）中P-700光氧化的程度进行了跟踪。在所有制剂中，超过90%的P-700+形成在pH值为10时通过添加连二亚硫酸钠而被消除。在类似条件下，结合的叶绿体铁硫蛋白的光还原也至少降低了90%。在连二亚硫酸钠存在下，叶绿体制剂的电子顺磁共振光谱表明，在消除初级光化学的条件下，结合的铁硫蛋白发生了化学还原。这些结果表明，P-700光氧化与结合的铁硫蛋白的光还原同时发生，并且这种铁硫蛋白作为光系统I的初级电子受体发挥作用。
