Givan C V, Givan A L, Leech R M
Department of Biology, University of York, Heslington, York, England.
Plant Physiol. 1970 May;45(5):624-30. doi: 10.1104/pp.45.5.624.
Intact chloroplasts isolated from leaves of Vicia faba L. var. the Sutton show a decline in the endogenous level of alpha-ketoglutarate upon illumination. alpha-Ketoglutarate supplied to the chloroplasts is similarly utilized in this light-dependent reaction, and its consumption is paralleled by a concomitant increase in the level of glutamate. There is no photostimulation of glutamate synthesis in chloroplasts broken by osmotic shock, but it can be somewhat restored by addition of ferredoxin and NADP. These results suggest that in the isolated chloroplast the synthesis of glutamate from alpha-ketoglutarate is regulated by the availability of reduced pyridine nucleotide generated by photosynthetic electron transport. This conclusion is supported by the finding of an apparent competition between the photoreduction of phosphoglycerate to triose phosphate and the photoutilization of alpha-ketoglutarate.
从蚕豆（Vicia faba L. var. the Sutton）叶片中分离出的完整叶绿体在光照下，内源性α-酮戊二酸水平会下降。供给叶绿体的α-酮戊二酸在这种光依赖反应中同样被利用，其消耗伴随着谷氨酸水平的相应增加。经渗透压冲击破碎的叶绿体中谷氨酸合成没有光刺激作用，但添加铁氧还蛋白和NADP可使其部分恢复。这些结果表明，在分离的叶绿体中，由α-酮戊二酸合成谷氨酸受光合电子传递产生的还原型吡啶核苷酸可用性的调节。磷酸甘油酸光还原为磷酸丙糖与α-酮戊二酸的光利用之间存在明显竞争这一发现支持了这一结论。
