Lehrstuhl für Biochemie der Pflanzen der Universität Göttingen, Göttingen, Germany.
Planta. 1971 Sep;99(3):222-9. doi: 10.1007/BF00386840.
Mature spinach plants were held in the dark for several days. The photochemical activities and the activity of some enzymes related to NADP reduction were follwed in the chloroplasts isolated from leaves after dark starvation. Photosystem-II, measured by reduction of DPIP, remained stable during 6 days of darkening. The decrease of NADP reduction which appeared after 2 days of starvation was found to be due to protein autolysis rather than inactivation of the photosystems. The stability of photosystem-I was demonstrated by reactivation of NADP reduction after addition of purified ferredoxin and ferredoxin-NADP-reductase. After 4 days of starvation the restoration of the NADP reduction required in addition another, low-molecular-weight factor. From the isolation procedure and from its properties this factor is assumed to be identical with FRS. However, even in the presence of FRS only half of the total activity is restored after 7 days. The activity of the NADP-reducing system is restored in vivo when plants kept for 7 days in the dark are again illuminated.
成熟的菠菜植株在黑暗中放置数天。在黑暗饥饿后从叶片中分离的叶绿体中，追踪了光化学活性和与 NADP 还原相关的一些酶的活性。通过 DPIP 的还原测量的光系统 II 在黑暗处理 6 天期间保持稳定。饥饿 2 天后出现的 NADP 还原减少被发现是由于蛋白质自溶而不是光系统失活。添加纯化的铁氧还蛋白和铁氧还蛋白-NADP-还原酶后，NADP 还原的再激活证明了光系统 I 的稳定性。饥饿 4 天后，除了另一种低分子量因子外，还需要恢复 NADP 还原。从分离程序及其特性来看，该因子被假定与 FRS 相同。然而，即使存在 FRS，7 天后也只能恢复总活性的一半。当在黑暗中放置 7 天的植物再次被光照时，NADP 还原系统的活性在体内得到恢复。
