Shephard D C, Levin W B
J Cell Biol. 1972 Aug;54(2):279-94. doi: 10.1083/jcb.54.2.279.
The ability of chloroplasts isolated from Acetabulana mediterranea to synthesize the protein amino acids has been investigated. When this chloroplast isolate was presented with (14)CO(2) for periods of 6-8 hr, tracer was found in essentially all amino acid species of their hydrolyzed protein Phenylalanine labeling was not detected, probably due to technical problems, and hydroxyproline labeling was not tested for The incorporation of (14)CO(2) into the amino acids is driven by light and, as indicated by the amount of radioactivity lost during ninhydrin decarboxylation on the chromatograms, the amino acids appear to be uniformly labeled. The amino acid labeling pattern of the isolate is similar to that found in plastids labeled with (14)CO(2) in vivo. The chloroplast isolate did not utilize detectable amounts of externally supplied amino acids in light or, with added adenosine triphosphate (ATP), in darkness. It is concluded that these chloroplasts are a tight cytoplasmic compartment that is independent in supplying the amino acids used for its own protein synthesis. These results are discussed in terms of the role of contaminants in the observed synthesis, the "normalcy" of Acetabularia chloroplasts, the synthetic pathways for amino acids in plastids, and the implications of these observations for cell compartmentation and chloroplast autonomy.
对从地中海伞藻中分离出的叶绿体合成蛋白质氨基酸的能力进行了研究。当向这种分离的叶绿体提供（14）CO₂ 6 - 8小时时，在其水解蛋白质的基本上所有氨基酸种类中都发现了示踪剂。未检测到苯丙氨酸标记，可能是由于技术问题，并且未测试羟脯氨酸标记。（14）CO₂ 掺入氨基酸是由光驱动的，并且如色谱图上茚三酮脱羧过程中损失的放射性量所示，氨基酸似乎被均匀标记。分离物的氨基酸标记模式与体内用（14）CO₂ 标记的质体中发现的模式相似。分离的叶绿体在光照下不利用可检测量的外部供应氨基酸，在黑暗中添加三磷酸腺苷（ATP）时也不利用。得出的结论是，这些叶绿体是一个紧密的细胞质区室，在供应用于自身蛋白质合成的氨基酸方面是独立的。从污染物在观察到的合成中的作用、伞藻叶绿体的“正常状态”、质体中氨基酸的合成途径以及这些观察结果对细胞区室化和叶绿体自主性的影响等方面讨论了这些结果。
