Distinct photorespiratory reactions are preferentially catalyzed by glutamate:glyoxylate and serine:glyoxylate aminotransferases in rice

文献类型： 外文期刊

第一作者： Zhang, Zhisheng

作者： Zhang, Zhisheng;Peng, Xinxiang;Zhang, Zhisheng;Ou, Juanying;Peng, Xinxiang;Mao, Xingxue;Zhang, Zhisheng;Ye, Nenghui;Zhang, Jianhua

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期刊名称：JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY （ 影响因子：6.252； 五年影响因子：5.375 ）

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收录情况： SCI

摘要： The metabolic function of glutamate:glyoxylate aminotransferase (GGAT) and serine:glyoxylate aminotransferase (SGAT) for photorespiration is still not exactly understood so far though it is mostly held that both enzymes may work in parallel in the reaction of glyoxylate to glycine during photorespiration of plants. Here, for the first time, we define the genes encoding GGAT and SGAT and report their biochemical and enzymatic properties in rice plants, in contrast to those from other plant species. Noticeably, GGAT exhibited approximately 18 fold higher catalytic efficiency (K-cat/K-m) with glyoxylate and glutamate than SGAT with glyoxylate and serine, and additionally, rice leaves usually contain 3-4 times higher abundance of glutamate relative to serine, implicating that GGAT may preferentially utilize glyoxylate to form glycine over SGAT. When SCAT or GGAT activity was regulated by gene transformation or nitrogen deficiency, respectively, it was observed that the glycine content was positively related to GGAT activities, while both serine and glycine contents were negatively related to SGAT activities. The results suggest that GGAT preferentially catalyzes the conversion of glyoxylate into glycine while SGAT is mainly responsible for the transamination reaction of serine to hydroxypyruvate in the photorespiratory pathway of rice. (C) 2014 Elsevier B.V. All rights reserved.

分类号： Q`O6

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