期刊
PLANT PHYSIOLOGY
卷 143, 期 1, 页码 530-539出版社
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.106.091330
关键词
-
Glutamate (Glu) dehydrogenase (GDH, EC 1.4.1.2 - 1.4.1.4) catalyzes in vitro the reversible amination of 2-oxoglutarate to Glu. The in vivo direction(s) of the GDH reaction in higher plants and hence the role(s) of this enzyme is unclear, a situation confounded by the existence of isoenzymes comprised totally of either GDHb-beta (isoenzyme 1) or alpha-(isoenzyme 7) subunits, as well as another five alpha-beta isoenzyme permutations. To clarify the in vivo direction of the reaction catalyzed by GDH isoenzyme 1, [N-15] Glu was supplied to roots of two independent transgenic tobacco (Nicotiana tabacum) lines with increased isoenzyme 1 levels (S4-H and S49-H). The [N-15] ammonium(NH4+) accumulation rate in these lines was elevated approximately 65% compared with a null segregant control line, indicating that isoenzyme 1 catabolizes Glu in roots. Leaf glutamine synthetase (GS) was inhibited with a GS-specific herbicide to quantify any contribution by GDH toward photorespiratory NH4+ reassimilation. Transgenic line S49-H did not show enhanced resistance to the herbicide, indicating that the large pool of isoenzyme 1 in S49-H leaves was unable to compensate for GS and suggesting that isoenzyme 1 does not assimilate NH4+ in vivo.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据