Department of Biology, Brandeis University, Waltham, Massachusetts 02154.
Plant Physiol. 1969 Aug;44(8):1115-21. doi: 10.1104/pp.44.8.1115.
The inhibition of photosynthetic CO(2) fixation by O(2), commonly referred to as the Warburg effect, was examined in isolated intact spinach (Spinacia oleracea) chloroplasts. The major characteristics of this effect in isolated chloroplasts are rapid reversibility when O(2) is replaced by N(2), an increased inhibition by O(2) at low concentrations of CO(2) and a decreased effect of O(2) with increased concentrations of CO(2).Both the DPN- and TPN-linked glyceraldehyde 3-phosphate dehydrogenases but not aldolase were inhibited by O(2). The photoreduction of TPN measured in fragmented chloroplast preparations was similar in N(2) and O(2) down to a concentration of 5 micromolar TPN. The effect of 100% O(2) on (14)CO(2) assimilation was overcome completely by fructose 1,6-diphosphate and by ribose 5-phosphate but not by ascorbate, cysteine, dithiothreitol and reduced lipoate. Glycolate became the major photosynthetic product at high partial pressures of O(2) or at low CO(2) concentrations. It is concluded that O(2) depresses photosynthesis primarily by causing a shift of a major portion of the total carbon into glycolate and impairing the functioning of the photosynthetic carbon reduction cycle. The mechanism whereby O(2) alters the flow of carbon into glycolate remains unknown.
氧对光合作用 CO2 固定的抑制作用，通常被称为瓦堡效应，在分离的完整菠菜（Spinacia oleracea）叶绿体中进行了研究。在分离的叶绿体中，该效应的主要特征是当 O2 被 N2 取代时迅速可逆，在低浓度 CO2 下 O2 的抑制作用增加，而在 CO2 浓度增加时 O2 的作用减小。O2 抑制 DPN 和 TPN 连接的甘油醛 3-磷酸脱氢酶，但不抑制醛缩酶。在碎片状叶绿体制剂中测量的 TPN 光还原在 N2 和 O2 中相似，直至 TPN 的浓度达到 5 微摩尔。100%O2 对（14）CO2 同化的影响可被果糖 1,6-二磷酸和核糖 5-磷酸完全克服，但不能被抗坏血酸、半胱氨酸、二硫苏糖醇和还原型 lipoate 克服。在高分压 O2 或低 CO2 浓度下，甘氨酸成为主要的光合作用产物。因此，O2 主要通过引起大部分总碳进入甘氨酸并损害光合作用碳还原循环的功能来抑制光合作用。O2 改变碳进入甘氨酸的流动的机制尚不清楚。
