叶绿体呼吸作用和光合作用电子传递链与光还原和氢氧反应的关联。
Association of the Chloroplastic Respiratory and Photosynthetic Electron Transport Chains of Chlamydomonas reinhardii with Photoreduction and the Oxyhydrogen Reaction.
机构信息
Institute for Photobiology of Cells and Organelles, Brandeis University, Waltham, Massachusetts 02254.
出版信息
Plant Physiol. 1986 Feb;80(2):364-8. doi: 10.1104/pp.80.2.364.
The hydrogenase-dependent processes, photoreduction and the dark oxyhydrogen reaction, both of which can support CO(2) assimilation, were compared with aerobic photosynthesis and respiration for their sensitivity to electron transport inhibitors in cells and intact chloroplasts of Chlamydomonas reinhardii 11-32/6. Photoreduction but not photosynthesis was inhibited in chloroplasts and the oxyhydrogen reaction detected only in cells was inhibited up to 75 and 90%, respectively, by 150 micromolar rotenone, indicating the involvement of a NAD(P)H-plastoquinone oxidoreductase in the hydrogen utilizing pathways. The oxyhydrogen reaction coupled to CO(2) fixation was inhibited more than 95% by 10 micromolar 2,5 - dibromo - 3 - methyl - 6 - isopropyl - p - benzoquinone (DBMIB), a concentration which did not affect respiratory activity. In cells, both photoreduction and the oxyhydrogen reaction exhibited a similar sensitivity to salicylhydroxamic acid (SHAM) showing approximately 90% inhibition by 7 millimolar concentration. Photosynthesis was inhibited only 30% by the same concentration of SHAM. Antimycin A (18 micromolar, 10 micrograms per milliliter) inhibited both photoreduction (80%) and the oxyhydrogen reaction (92%) in cells with the oxyhydrogen reaction being approximately 10 times more sensitive to lower concentrations of the inhibitor. Antimycin A at 18 micromolar concentration did not inhibit photosynthetic CO(2) fixation unless the cells were adapted to an atmosphere of N(2) and the reaction conducted anaerobically. Photosynthesis, photoreduction, and the oxyhydrogen reaction coupled to CO(2) fixation were all inhibited greater than 90% by 10 micromolar carbonylcyanide-p-trifluoromethoxyphenylhydrazone. ATP added to chloroplasts adapted to an atmosphere of H(2) could support CO(2) uptake in the dark. These results are interpreted as evidence that photoreduction and the oxyhydrogen reaction involve some common components of thylakoidal electron transport pathways in Chlamydomonas including NAD(P)H-plastoquinone oxidoreductase and the plastoquinone pool. An O(2)-consuming thylakoidal or mitochondrial reaction is an additional component of the oxyhydrogen reaction.
依赖氢化酶的过程，光还原和暗的氢氧反应，都可以支持 CO2 同化，与有氧光合作用和呼吸作用相比，它们对电子传递抑制剂在细胞和完整的衣藻 11-32/6 叶绿体中的敏感性进行了比较。光还原但不是光合作用在叶绿体中被抑制，而仅在细胞中检测到的氢氧反应分别被 150 微摩尔鱼藤酮抑制了 75%和 90%，表明 NAD(P)H-质体醌氧化还原酶参与了氢利用途径。与 CO2 固定偶联的氢氧反应被 10 微摩尔 2,5-二溴-3-甲基-6-异丙基-p-苯醌（DBMIB）抑制超过 95%，这种浓度不影响呼吸活性。在细胞中，光还原和氢氧反应对水杨基羟肟酸（SHAM）表现出相似的敏感性，7 毫摩尔浓度下约有 90%的抑制作用。相同浓度的 SHAM 仅抑制光合作用 30%。抗霉素 A（18 微摩尔，10 微克/毫升）在细胞中抑制光还原（80%）和氢氧反应（92%），其中氢氧反应对抑制剂的低浓度更敏感约 10 倍。在 18 微摩尔浓度下，除非细胞适应于 N2 气氛并且反应在厌氧条件下进行，否则抗霉素 A 不会抑制光合 CO2 固定。光合作用、光还原和与 CO2 固定偶联的氢氧反应均被 10 微摩尔羰基氰化物-p-三氟甲氧基苯腙抑制大于 90%。添加到适应于 H2 气氛的叶绿体中的 ATP 可以在黑暗中支持 CO2 的摄取。这些结果被解释为证据，表明光还原和氢氧反应涉及衣藻中类囊体电子传递途径的一些共同成分，包括 NAD(P)H-质体醌氧化还原酶和质体醌库。O2 消耗的类囊体或线粒体反应是氢氧反应的另一个组成部分。
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