Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, 94720, Berkeley, CA, USA.
Planta. 1979 Jan;145(4):377-82. doi: 10.1007/BF00388364.
Hydrogen peroxide (6x10(-4) M) causes a 90% inhibition of CO2-fixation in isolated intact chloroplasts. The inhibition is reversed by adding catalase (2500 U/ml) or DTT (10 mM). If hydrogen peroxide is added to a suspension of intact chloroplasts in the light, the incorporation of carbon into hexose- and heptulose bisphosphates and into pentose monophosphates is significantly increased, whereas; carbon incorporation into hexose monophosphates and ribulose 1,5-bisphosphate is decreased. At the same time formation of 6-phosphogluconate is dramatically stimulated, and the level of ATP is increased. All these changes induced by hydrogen peroxide are reversed by addition of catalase or DTT. Additionally, the conversion of [(14)C]glucose-6-phosphate into different metabolites by lysed chloroplasts in the dark has been studied. In presence of hydrogen peroxide, formation of ribulose-1,5-bisphosphate is inhibited, whereas formation of other bisphosphates,of triose phosphates, and pentose monophosphates is stimulated. Again, DTT has the opposite effect. The release of (14)CO2 from added [(14)C]glucose-6-phosphate by the soluble fraction of lysed chloroplasts via the reactions of oxidative pentose phosphate cycle is completely inhibited by DTT (0.5 mM) and re-activated by comparable concentrations of hydrogen peroxide. These results indicate that hydrogen peroxide interacts with reduced sulfhydryl groups which are involved in the light activation of enzymes of the Calvin cycle at the site of fructose- and sedoheptulose bisphophatase, of phosphoribulokinase, as well as in light-inactivation of oxidative pentose phosphate cycle at the site of glucose-6-phosphate dehydrogenase.
过氧化氢（6x10(-4) M）会导致分离完整的叶绿体中的 CO2 固定率降低 90%。这种抑制作用可以通过添加过氧化氢酶（2500 U/ml）或 DTT（10 mM）来逆转。如果将过氧化氢添加到光下完整的叶绿体悬浮液中，碳会显著地掺入己糖-和庚糖-1,7-二磷酸以及戊糖-1-磷酸中，而己糖-1-磷酸和核酮糖 1,5-二磷酸中的碳掺入则减少。同时，6-磷酸葡萄糖酸的形成显著增加，ATP 水平也升高。所有这些由过氧化氢引起的变化都可以通过添加过氧化氢酶或 DTT 来逆转。此外，还研究了黑暗中裂解叶绿体中 [(14)C]葡萄糖-6-磷酸转化为不同代谢物的情况。在过氧化氢存在的情况下，核酮糖-1,5-二磷酸的形成受到抑制，而其他二磷酸、三糖磷酸和戊糖-1-磷酸的形成则受到刺激。再次，DTT 则具有相反的作用。通过裂解叶绿体的可溶性部分通过氧化戊糖磷酸循环的反应将添加的 [(14)C]葡萄糖-6-磷酸释放为 (14)CO2，该反应完全被 DTT（0.5 mM）抑制，并通过可比浓度的过氧化氢重新激活。这些结果表明，过氧化氢与还原型巯基相互作用，这些巯基参与了果糖-和 sedoheptulose 双磷酸酶、磷酸核糖激酶的 Calvin 循环酶的光激活，以及葡萄糖-6-磷酸脱氢酶的氧化戊糖磷酸循环的光失活。
