Distribution of two isoforms of glutamine synthetase in bundle sheath and mesophyll cells of corn leaves
Distribution of two isoforms of glutamine synthetase in bundle sheath and mesophyll cells of corn leaves
复制标题
谷氨酰胺合成酶两种异构体在玉米叶片束鞘和叶肉细胞中的分布
DOI：
10.1111/j.1399-3054.1988.tb06617.x
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
A. Oaks
中科院分区：
文献类型：
--
作者：
T. Yamaya;A. Oaks
采用离子交换色谱法研究了谷氨酰胺合成酶（GS; EC 6.3.1.2）在玉米（Zea mays L. var. W64A × W182E）叶片叶肉细胞和束鞘细胞中的定位。在全叶提取物中，GS1（胞质GS）和GS2（叶绿体GS）的相对活性几乎相等。纯化的叶肉原生质体和束鞘链也显示出相似的GS1和GS2比例。当叶肉原生质体与亚硝酸盐孵育或束鞘束与甘氨酸孵育时，蛋氨酸亚砜亚胺（1 mM）增加了氨的积累。这清楚地表明，光呼吸和NOJ还原对NH+4的代谢存在空间分离。
Localization of two isoforms of glutamine synthetase (GS; EC 6.3.1.2) was investigated in different cell types, mesophyll cells and bundle sheath cells, of corn (Zea mays L. var. W64A × W182E) leaves by using ion exchange chrotnatography. In whole leaf extracts, relative activities of GS1 (cytosolic GS) and GS2 (chloroplastic GS) were almost equal. Purified mesophyll protoplasts and bundle sheath strands also showed similar proportions of GS1 and GS2. Methionine sulfoximine (1 mM) enhanced the accumulation of ammonia when mesophyll protoplasts were incubated with nitrite or when bundle sheath strands were incubated with glycine. This clearly indicates a spatial separation of metabolism of NH+4 derived from photorespiration and from reduction of NOJ.