Peterhansel Christoph, Horst Ina, Niessen Markus, Blume Christian, Kebeish Rashad, Kürkcüoglu Sophia, Kreuzaler Fritz
Arabidopsis Book. 2010;8:e0130. doi: 10.1199/tab.0130. Epub 2010 Mar 23.
Photorespiration is initiated by the oxygenase activity of ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCO), the same enzyme that is also responsible for CO(2) fixation in almost all photosynthetic organisms. Phosphoglycolate formed by oxygen fixation is recycled to the Calvin cycle intermediate phosphoglycerate in the photorespiratory pathway. This reaction cascade consumes energy and reducing equivalents and part of the afore fixed carbon is again released as CO(2). Because of this, photorespiration was often viewed as a wasteful process. Here, we review the current knowledge on the components of the photorespiratory pathway that has been mainly achieved through genetic and biochemical studies in Arabidopsis. Based on this knowledge, the energy costs of photorespiration are calculated, but the numerous positive aspects that challenge the traditional view of photorespiration as a wasteful pathway are also discussed. An outline of possible alternative pathways beside the major pathway is provided. We summarize recent results about photorespiration in photosynthetic organisms expressing a carbon concentrating mechanism and the implications of these results for understanding Arabidopsis photorespiration. Finally, metabolic engineering approaches aiming to improve plant productivity by reducing photorespiratory losses are evaluated.
光呼吸由核酮糖-1,5-二磷酸羧化酶/加氧酶（RUBISCO）的加氧酶活性引发，几乎所有光合生物中负责二氧化碳固定的也是这种酶。通过氧固定形成的磷酸乙醇酸在光呼吸途径中被循环回卡尔文循环中间产物磷酸甘油酸。这个反应级联消耗能量和还原当量，部分先前固定的碳又以二氧化碳的形式释放出来。因此，光呼吸常常被视为一个浪费的过程。在这里，我们综述了目前关于光呼吸途径组成部分的知识，这些知识主要是通过拟南芥的遗传学和生物化学研究获得的。基于这些知识，计算了光呼吸的能量成本，但也讨论了许多挑战光呼吸是浪费途径这一传统观点的积极方面。提供了主要途径之外可能的替代途径概述。我们总结了表达碳浓缩机制的光合生物中光呼吸的最新结果以及这些结果对理解拟南芥光呼吸的意义。最后，评估了旨在通过减少光呼吸损失来提高植物生产力的代谢工程方法。
