Kinetics and Apparent K(m) of Oxygen Cycle under Conditions of Limiting Carbon Dioxide Fixation.
Kinetics and Apparent K(m) of Oxygen Cycle under Conditions of Limiting Carbon Dioxide Fixation.
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限制二氧化碳固定条件下氧循环的动力学和表观 K(m)。
DOI：
10.1104/pp.61.6.915
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发表时间：
1978
期刊：
影响因子：
7.4
通讯作者：
O. Ollinger
中科院分区：
文献类型：
--
作者：
R. Radmer;B. Kok;O. Ollinger
利用膜式质谱仪监测光驱动藻类悬浮液中O（2）释放、O（2）吸收和CO（2）吸收。我们观察到以下情况。(a)在碘乙酰胺存在的情况下，O（2）的吸收率取代了CO（2）的吸收率，在超过约30%O（2）时显示出明显的平台（V（max）），在约8%O（2）时为半最大值。我们的结论是，这种光驱动的O（2）吸收过程，这不涉及碳化合物，饱和在较低的O（2）浓度比光呼吸和乙醇酸形成。(b)在没有抑制剂的情况下，O（2）的释放相对不受CO（2）存在或不存在的影响。在CO（2）耗尽过程中，流向CO（2）的电子被流向O（2）的电子所取代。(c)在CO（2）吸收的停止和O（2）吸收的增加之间有一个明显的延迟。我们将这种延迟归因于另一种电子受体的瞬时利用，可能是碳酸氢盐或CO（2）的另一种结合形式。
A mass spectrometer with a membrane inlet was used to monitor light-driven O(2) evolution, O(2) uptake, and CO(2) uptake in suspensions of algae (Scenedesmus obliquus). We observed the following. (a) The rate of O(2) uptake, which, in the presence of iodoacetamide, replaces the uptake of CO(2), showed a distinct plateau (V(max)) beyond approximately 30% O(2) and was half-maximal at approximately 8% O(2). We concluded that this light-driven O(2) uptake process, which does not involve carbon compounds, is saturated at lower O(2) concentrations than are photorespiration and glycolate formation. (b) In the absence of inhibitor, O(2) evolution was relatively unaffected by the presence or absence of CO(2). During the course of CO(2) depletion, electron flow to CO(2) was replaced by an equivalent flow to O(2). (c) There was a distinct delay between the cessation of CO(2) uptake and the increase in O(2) uptake. We ascribe this delay to the transient utilization of another electron acceptor-possibly bicarbonate or another bound form of CO(2).