Institute for Photobiology of Cells and Organelles, Brandeis University, Waltham, Massachusetts 02254.
Plant Physiol. 1992 Nov;100(3):1361-5. doi: 10.1104/pp.100.3.1361.
The oxyhydrogen reaction (the reduction of O(2) to water by H(2)) in the presence of CO(2) was studied in the isolated Chlamydomonas reinhardtii chloroplast by monitoring the rate of (14)CO(2) incorporation into acid-stable products in the dark. The endogenous rate of CO(2) uptake (50-125 nmol/mg chlorophyll per h) was increased about 3- to 4-fold by ATP and additionally when combined with glucose, ribose-5-phosphate, and glycerate-3-phosphate. The rate was diminished 50 to 75%, respectively, when H(2) was replaced by N(2) or by air. Decrease in CO(2) uptake by dl-glyceraldehyde was taken to indicate that the regenerative phase and complete Calvin cycle turnover were involved. Diminution of CO(2) incorporation by rotenone, antimycin A, and 2,5-dibromo-3-methyl-6-isopropanol-p-benzoquinone was attributed to an inhibition of the oxyhydrogen reaction, resulting in an elevated NADPH/NADP ratio. If so, then the diminished CO(2) uptake could have been by "product inhibition" of the carbon metabolic network. Our data are consistent with the proposal (H. Gaffron [1942] J Gen Physiol 26: 241-267) that CO(2) fixation coupled to the oxyhydrogen reaction is dependent to some extent on exchloroplastic metabolism. This support is primarily ATP provided by mitochondrial respiration.
在二氧化碳存在的情况下，通过监测（14）CO2在黑暗中掺入酸稳定产物的速率，研究了分离的莱茵衣藻叶绿体中的氢氧反应（H2将 O2还原为水）。内源性 CO2摄取率（每毫克叶绿素 50-125 nmol/h）通过 ATP 增加了约 3-4 倍，当与葡萄糖、核糖-5-磷酸和甘油酸-3-磷酸结合使用时，还会进一步增加。当用氮气或空气代替氢气时，速率分别减少了 50%到 75%。dl-甘油醛对 CO2摄取的减少表明涉及到再生阶段和完整的卡尔文循环周转。鱼藤酮、antimycin A 和 2,5-二溴-3-甲基-6-异丙醇-p-苯醌对 CO2掺入的减少归因于氢氧反应的抑制，导致 NADPH/NADP 比值升高。如果是这样，那么 CO2摄取的减少可能是由于碳代谢网络的“产物抑制”。我们的数据与 H. Gaffron（1942）的提议一致，即与氢氧反应偶联的 CO2固定在某种程度上依赖于叶绿体间代谢。这种支持主要是由线粒体呼吸提供的 ATP。
