Particle Separation Facility, Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey 08903.
Plant Physiol. 1974 Oct;54(4):532-4. doi: 10.1104/pp.54.4.532.
Chloroplast suspensions from spinach (Spinacia oleracea L.) were clearly resolved into intact and stripped chloroplasts by isopycnic centrifugation in density gradients of silica sol ("Ludox") and polyethlene glycol. The intact chloroplasts fixed CO(2) and evolved O(2) more rapidly than the crude suspensions; the stripped chloroplasts were inactive. During the photosynthetic fixation of (14)CO(2) in the intact chloroplasts recovered from the gradient, the (14)C label was observed to spread through the photosynthetic intermediate pools, as well as into starch, which indicates that the purified chloroplasts are metabolically competent. This appears to be the first report of the retention of photosynthetic activity following the purification of chloroplasts in density gradients.
菠菜（Spinacia oleracea L.）叶绿体悬浮液可通过硅胶溶胶（"Ludox"）和聚乙二醇密度梯度等密度离心法清晰地区分为完整和去垢的叶绿体。完整的叶绿体比粗悬液更快地固定 CO(2)并释放 O(2)；去垢的叶绿体则没有活性。在从梯度中回收的完整叶绿体中进行（14）CO(2)的光合固定时，观察到（14）C 标记物在光合中间产物库中扩散，以及进入淀粉，这表明纯化的叶绿体具有代谢能力。这似乎是首次报道在密度梯度中纯化叶绿体后仍保留光合作用活性。
