CYANOPSIN, A NEW PIGMENT OF CONE VISION
CYANOPSIN, A NEW PIGMENT OF CONE VISION
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DOI：
10.1126/science.118.3070.505
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发表时间：
1953-01-01
期刊：
影响因子：
56.9
通讯作者：
SMITH, PH
中科院分区：
文献类型：
--
作者：
WALD, G;BROWN, PK;SMITH, PH
目前已知的三种视色素是由两种视黄素和两种视蛋白或视蛋白的组合形成的。视网膜1与杆状视蛋白（视紫红蛋白）结合生成视紫红蛋白，或与锥状视蛋白（视紫红蛋白）结合生成碘视蛋白。Retinene2与杆状视蛋白结合形成卟啉蛋白（1-3）。显然，第四种组合是可能的：视黄醛2和视锥蛋白。现在已经准备好了。它是一种蓝色的光敏颜料，在620混合时吸收最大。我们建议叫它蓝视色素。合成方法如下。从鸡视网膜中提取的适应黑暗的视杆细胞和视锥细胞含有视紫红质和碘紫红质的混合物。在视紫红质不敏感的深红光下，碘视蛋白被不可逆地漂白成全反式视黄蛋白和视锥蛋白的混合物。在此基础上加入少量特定的视黄嘌呤2的顺式异构体，当与杆状视蛋白混合时，形成卟啉（2,3）。在这种情况下加入锥视蛋白，形成视蛋白。在室温下，在黑暗中5分钟内完成青紫素的合成。在黑暗中测量所得溶液的吸收光谱，在深红光中漂白后再次测量吸收光谱。前者的光谱减去后者的光谱就是青紫素的差谱。如图1所示。
HE three visual pigments known heretofore are formed by combinations between two retinenes and two visual proteins or opsins. Retinene1 combines with rod opsin (scotopsin) to make rhodopsin, or with cone opsin (photopsin) to make iodopsin. Retinene2 combines with rod opsin to make porphyropsin (1-3). Clearly a fourth combination is possible: retinene2 with cone opsin. This has now been prepared. It is a blue, light-sensitive pigment, with an absorption maximum at 620 mix. We propose to call it cyanopsin. It is synthesized as follows. An extract of dark-adapted rods andcones from the chicken retina contains a mixture of rhodopsin and iodopsin. With deep red light, to which rhodopsin is insensitive, the iodopsin alone is bleached irreversibly to a mixture of alltrans retinene1 and cone opsin. To this is added a small amount of the specific cis isomer of retinene2 which, when mixed with rod opsin, forms porphyropsin (2, 3). Added in this instance to cone opsin, it forms eyanopsin.The synthesis of cyanopsin is completed within 5 minutes in the dark at room temperature. The absorption spectrum of the resulting solution is measured in the dark, and again after bleaching in deep red light. The former spectrum minus the latter is the difference spectrum of cyanopsin. Thisis shown in Fig. 1.