Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie, Universität München, Goethestraße 33, D-8000, München 2, Federal Republic of Germany.
Planta. 1980 Jun;149(1):48-51. doi: 10.1007/BF00386226.
The salts of several weak acids have been used to render the envelope permeable to protons. In order to investigate the role of stromal pH changes in the light regulation of CO2 fixation, formate, octanoate, nitrite, and glyoxylate have been tried as tools to reverse the light-dependent alkalization of the stroma. For this purpose, the decrease of the stromal pH in illuminated spinach chloroplasts, as caused by the addition of these substances or by instantaneous lowering of the pH in the medium, has been compared with the corresponding decrease of CO2 fixation and the change of stromal metabolite levels. It appears from out data that formate and octanoate are suited best to obtain a specific inhibition of CO2 fixation by lowering the stromal pH. The measurement of the corresponding metabolite levels indicates that this inhibition is primarily due to an inhibition of fructose- and sedoheptulose bisphosphatase. It is concluded that these two enzymes are important regulatory steps for the light control of CO2 fixation.
已经使用几种弱酸的盐来使包膜对质子具有通透性。为了研究基质 pH 值变化在 CO2 固定的光调节中的作用，已经尝试使用甲酸盐、辛酸盐、亚硝酸盐和乙醛酸作为逆转基质光依赖性碱化的工具。为此，添加这些物质或瞬时降低介质中的 pH 值导致的照光菠菜叶绿体基质 pH 值降低，与 CO2 固定的相应降低和基质代谢物水平的变化进行了比较。我们的数据表明，甲酸盐和辛酸盐最适合通过降低基质 pH 值来特异性抑制 CO2 固定。相应代谢物水平的测量表明，这种抑制主要是由于果糖-1,6-二磷酸和景天庚酮糖-1,7-二磷酸酶的抑制。结论是，这两种酶是 CO2 固定光控制的重要调节步骤。
