Glycine metabolism in intact leaves by in vivo 13C and 15N labeling
Glycine metabolism in intact leaves by in vivo 13C and 15N labeling
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DOI：
10.1074/jbc.m507053200
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发表时间：
2005-11-25
影响因子：
4.8
通讯作者：
Schaefer, J
中科院分区：
文献类型：
--
作者：
Cegelski, L;Schaefer, J
用(CO2)-C-13（亚环境浓度）标记的完整大豆叶片的固态C-13核磁共振测量表明，来自光呼吸C-2循环的过量甘氨酸（即甘氨酸不是支持光合作用的甘油生产的一部分）要么完全脱羧，要么作为C-13标记的甘氨酸残基插入蛋白质中。在(CO2)-C-13标记开始后2分钟内，13C在叶片蛋白中的掺入，由(NH4)-N-15 (NO3)-N-15均匀标记。在那些有效氮含量较低的叶片中（通过叶片硝酸盐和谷氨酰胺-谷氨酸浓度测量），多余的甘氨酸主要用作蛋白质中的甘氨酸残基。
Solid-state C-13 NMR measurements of intact soybean leaves labeled by (CO2)-C-13 ( at subambient concentrations) show that excess glycine from the photorespiratory C-2 cycle (i.e. glycine not part of the production of glycerate in support of photosynthesis) is either fully decarboxylated or inserted as C-13-labeled glycyl residues in proteins. This 13C incorporation in leaf protein, which is uniformly N-15 labeled by (NH4)-N-15 (NO3)-N-15, occurs as soon as 2 min after the start of (CO2)-C-13 labeling. In those leaves with lower levels of available nitrogen (as measured by leaf nitrate and glutamine-glutamate concentrations), the excess glycine is used primarily as glycyl residues in protein.