Smillie R M, Andersen K S, Tobin N F, Entsch B, Bishop D G
Plant Physiology Unit, Commonwealth Scientific and Industrial Research Organization, Division of Food Research, and School of Biological Sciences, Macquarie University, North Ryde, 2113, Sydney, Australia.
Plant Physiol. 1972 Apr;49(4):471-5. doi: 10.1104/pp.49.4.471.
Photoreduction of NADP from water in agranal chloroplasts isolated from the leaf bundle sheath cells of Zea mays (var. DS 606A) or Sorghum bicolor (var. Texas 610) was dependent upon addition of plastocyanin as well as ferredoxin. Activity was further increased by the addition of ferredoxin NADP-reductase. Saturation for plastocyanin was reached at about 6 micromolar. In contrast, grana-containing chloroplasts isolated from leaf mesophyll cells of these plants or from pea (Pisum sativum L.) leaves did not require either plastocyanin or ferredoxin NADP-reductase for NADP photoreduction from water, although with some preparations plastocyanin stimulated the activity.Photosystem I activity, which was low in washed preparations of bundle sheath chloroplasts, was also stimulated by plastocyanin. The effect of plastocyanin on photosystem I activity in the grana-containing chloroplasts was similar to that on NADP photoreduction from water.In the presence of plastocyanin, the rates of NADP photoreduction from water were about the same in the agranal and granal chloroplasts, but photosystem I activity was considerably higher in bundle sheath chloroplasts. In these chloroplasts photosystem II appeared to limit the rate of NADP photoreduction.The results indicated that the agranal bundle sheath chloroplasts reduced plastocyanin via photosystem II and oxidized it via photosystem I. Both types of maize chloroplast photoreduced oxidized plastocyanin, but in the presence of methyl viologen, reduced plastocyanin was photo-oxidized only by the bundle sheath chloroplasts.
从玉米（品种DS 606A）或高粱（品种Texas 610）叶束鞘细胞分离得到的无基粒叶绿体中，利用水光还原NADP依赖于质体蓝素和铁氧还蛋白的添加。添加铁氧还蛋白NADP还原酶可进一步提高活性。质体蓝素的饱和浓度约为6微摩尔。相比之下，从这些植物的叶肉细胞或豌豆（Pisum sativum L.）叶片分离得到的含基粒叶绿体，利用水光还原NADP时不需要质体蓝素或铁氧还蛋白NADP还原酶，不过某些制备物中质体蓝素会刺激活性。在束鞘叶绿体的洗涤制备物中较低的光系统I活性，也受到质体蓝素的刺激。质体蓝素对含基粒叶绿体中光系统I活性的影响，与对利用水光还原NADP的影响相似。在有质体蓝素存在时，无基粒和含基粒叶绿体中利用水光还原NADP的速率大致相同，但束鞘叶绿体中的光系统I活性要高得多。在这些叶绿体中，光系统II似乎限制了NADP还原的速率。结果表明，无基粒束鞘叶绿体通过光系统II还原质体蓝素，并通过光系统I将其氧化。两种类型的玉米叶绿体都能光还原氧化型质体蓝素，但在甲基紫精存在时，还原型质体蓝素仅被束鞘叶绿体光氧化。
