Catalytic and functional aspects of different isozymes of glycolate oxidase in rice.
Catalytic and functional aspects of different isozymes of glycolate oxidase in rice.
复制标题
水稻乙醇酸氧化酶不同同工酶的催化和功能方面
DOI：
10.1186/s12870-017-1084-5
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发表时间：
2017-08-08
影响因子：
5.3
通讯作者：
Peng X
中科院分区：
文献类型：
--
作者：
Zhang Z;Li X;Cui L;Meng S;Ye N;Peng X
乙醇酸氧化酶（GLO）是植物光呼吸的关键酶。水稻中有4个GLO基因编码并形成不同的同工酶，但其功能差异尚不清楚。本研究对GLO同工酶的酶学和生理特性进行了比较分析。结果GLO1、GLO4和GLO1 + 4在酵母中异种表达时，对底物乙醇酸表现出最高的活性和最低的km， GLO3对底物乙醇酸和l -乳酸都表现出较高的活性和亲和力，GLO5对所有底物都不具有催化活性。为了进一步揭示每种GLO同工酶在植物中的生理作用，我们培育了多种GLO转基因水稻品系并对其进行了功能分析。GLO活性在inglo1和glo4过表达系中均显著升高。然而，当敲除glo1orglo4时，inglo1敲除系比inglo4敲除系活性受到的抑制要明显得多，并且两种敲除突变体都表现出明显的侏儒化表型。在glo3、glo5过表达系和RNAi系中，只有glo3过表达系的l -乳酸氧化活性显著增加，其他表型无明显变化。结论水稻GLO同工酶具有不同的酶学特性，可能具有不同的生理功能。
BackgroundGlycolate oxidase (GLO) is a key enzyme for photorespiration in plants. There are four GLO genes encoding and forming different isozymes in rice, but their functional differences are not well understood. In this study, enzymatic and physiological characteristics of the GLO isozymes were comparatively analyzed.ResultsWhen expressed heterologously in yeast, GLO1, GLO4 and GLO1 + 4 showed the highest activities and lowestKmfor glycolate as substrate, whereas GLO3 displayed high activities and affinities for both glycolate and L-lactate, and GLO5 was catalytically inactive with all substrates tested. To further reveal the physiological role of each GLO isozyme in plants, variousGLOgenetically modified rice lines were generated and functionally analyzed. GLO activity was significantly increased both inGLO1andGLO4overexpression lines. Nevertheless, when eitherGLO1orGLO4was knocked out, the activity was suppressed much more significantly inGLO1knockout lines than inGLO4knockout lines, and both knockout mutants exhibited obvious dwarfism phenotypes. AmongGLO3andGLO5overexpression lines and RNAi lines, onlyGLO3overexpression lines showed significantly increased L-lactate-oxidizing activity but no other noticeable phenotype changes.ConclusionsThese results indicate that rice GLO isozymes have distinct enzymatic characteristics, and they may have different physiological functions in rice.
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影响因子：
4.9
作者：
Kamada, T;Nito, K;Nishimura, M
通讯作者：
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影响因子：
6.4
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MUKHERJEE, SP;CHOUDHURI, MA
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作者：
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通讯作者：
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