SPECIES VARIATION IN THE SPECIFICITY OF RIBULOSE-BIPHOSPHATE CARBOXYLASE-OXYGENASE
SPECIES VARIATION IN THE SPECIFICITY OF RIBULOSE-BIPHOSPHATE CARBOXYLASE-OXYGENASE
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DOI：
10.1038/291513a0
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发表时间：
1981-01-01
期刊：
影响因子：
64.8
通讯作者：
OGREN, WL
中科院分区：
文献类型：
--
作者：
JORDAN, DB;OGREN, WL
许多物种（包括大多数农作物）的光合作用和光呼吸之间的平衡是由1，5-二磷酸核酮糖（RuBP）羧化酶/加氧酶的动力学特性决定的。光合作用由羧化酶活性启动，而加氧酶活性催化光呼吸途径中的第一个反应。在这些反应中，CO2和O2是竞争性底物。由于O2抑制羧化作用，而光呼吸作用将还原碳氧化为CO2，对植物没有已知的益处，因此光合效率和生产力可能通过增加羧化作用或减少氧合作用的酶的化学或遗传改变来增加。RuBP羧化酶/加氧酶不能完全区分CO2和O2，因此光呼吸是不可避免的。根据从几种不同物种[大豆、扩展四角藻、菠菜、多年生黑麦草、烟草、苋、玉米、栅列藻、莱茵衣藻、纤细裸藻、隐丝藻或flos-aguae、Cocochloris peniocystis、红色红球藻和球形红球藻]纯化的RuBP羧化酶/加氧酶的分析，证明了对底物CO2和O2的特异性的巨大差异。进化的压力似乎已经引导酶更有效地利用CO2。
The balance between photosynthesis and photorespiration in many species, including most crop plants, is determined by the kinetic properties of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase. Photosynthesis is initiated by the carboxylase activity while the oxygenase activity catalyses the 1st reaction in the photorespiratory pathway. In these reactions, CO2, and O2 are competitive substrates. Because O2 inhibits carboxylation and photorespiration oxidizes reduced carbon to CO2 with no known benefit to the plant, photosynthetic efficiency and productivity might be increased by chemically or genetic alterations of the enzyme which increase carboxylation or decrease oxygenation. RuBP carboxylase/oxygenase cannot completely discriminate between CO2 and O2, so that photorespiration is unavoidable. From analyses of RuBP carboxylase/oxygenase enzymes purified from several different species [Glycine max, Tetragonium expansa, Spinacia oleracea, Lolium perenne, Nicotiana tabacum, Amaranthus hybridus, Zea mays, Scenedesmus obliquus, Chlamydomonas reinhardii, Euglena gracilis, Aphanizomen or flos-aguae, Cocochloris peniocystis, Rhodospirillum rubrum and Rhodopseudomonas sphaeroides], large differences in specificity towards the substrates CO2 and O2 were demonstrated. Evolutionary pressures seem to have directed the enzyme towards more efficient utilization of CO2.