Yamamoto Keiichi, Shimada Kiyo, Ito Khoji, Hamada Saeko, Ishijima Akio, Tsuchiya Takayoshi, Tazawa Masashi
Department of Biology, Chiba University, Inage-ku, Chiba, 263-8522 Japan.
Plant Cell Physiol. 2006 Oct;47(10):1427-31. doi: 10.1093/pcp/pcl006. Epub 2006 Sep 8.
Recently, it was found that myosin generating very fast cytoplasmic streaming in Chara corallina has very high ATPase activity. To estimate the energy consumed by this myosin, its concentration in the internodal cells of C. corallina was determined by quantitative immunoblot. It was found that the concentration of Chara myosin was considerably high (200 nM) and the amount of ATP consumed by this myosin would exceed that supplied by dark respiration if all myosin molecules were fully activated by the interaction with actin. These results and model calculations suggested that the energy required to generate cytoplasmic streaming is very small and only one-hundredth of the existing myosin is enough to maintain the force for the streaming in the Chara cell.
最近发现，在珊瑚轮藻中产生极快速细胞质环流的肌球蛋白具有非常高的ATP酶活性。为了估算这种肌球蛋白消耗的能量，通过定量免疫印迹法测定了其在珊瑚轮藻节间细胞中的浓度。结果发现，轮藻肌球蛋白的浓度相当高（200 nM），如果所有肌球蛋白分子都通过与肌动蛋白的相互作用而被完全激活，那么这种肌球蛋白消耗的ATP量将超过暗呼吸所提供的ATP量。这些结果和模型计算表明，产生细胞质环流所需的能量非常小，仅现有肌球蛋白的百分之一就足以维持轮藻细胞中细胞质环流的动力。
