SCARPELLI D G, CRAIG E L
J Cell Biol. 1963 May;17(2):279-88. doi: 10.1083/jcb.17.2.279.
Nucleoside triphosphatase (NTPase) activity was demonstrated at the submicroscopic level in the frog retina by the Wachstein-Meisel method utilizing various purine and pyrimidine nucleosides. Under the electron microscope magnesium-activated NTPase was localized in the outer and inner segments, and in the plexiform layers. NTPase active sites in the cones were localized diffusely in the 70 to 80 A interspaces between the double membranes of the stacked lamellae and in the investing cytoplasm. In the rods, on the other hand, sites of activity were observed at the periphery of the stacked lamellae as discrete electron opaque deposits measuring 1000 to 1500 A which interdigitated between the lamellae for short distances. Deposits of reaction product appeared more numerous in rods of dark-adapted frogs stimulated with monochromatic light with a wave length of 510 mmicro. Enzyme activity was also observed in mitochondria of the rod and cone ellipsoids. In the outer and inner plexiform layers NTPase active sites were present on and between the membranes of axons and the plasma membranes of some of the neurons.
利用各种嘌呤和嘧啶核苷，通过瓦施泰因-迈泽尔方法在青蛙视网膜的亚微观水平上证实了核苷三磷酸酶（NTPase）活性。在电子显微镜下，镁激活的NTPase定位于外段和内段以及神经纤维层。视锥细胞中的NTPase活性位点分散定位于堆叠片层双膜之间70至80埃的间隙以及包绕的细胞质中。另一方面，在视杆细胞中，活性位点在堆叠片层的周边观察到，为离散的电子不透明沉积物，大小为1000至1500埃，在片层之间短距离内相互交错。在用波长为510微米的单色光刺激的暗适应青蛙的视杆细胞中，反应产物的沉积物似乎更多。在视杆细胞和视锥细胞的椭球体的线粒体中也观察到酶活性。在神经纤维层和内网层中，NTPase活性位点存在于轴突膜和一些神经元的质膜上以及它们之间。
