Department of Botany, School of Biological Sciences, The University, University Park, NG7 2RD, Nottingham, UK.
Planta. 1978 Jan;138(2):123-5. doi: 10.1007/BF00391167.
Platymonas striata Butcher displays significant levels of glutamate synthase (GS) (EC 2.6.1.53) and glutamine synthetase (GOGAT) (EC 6.3.1.2.), but very low levels of glutamate dehydrogenase (GDH) (EC 1.4.1.4). This suggests that the GS/GOGAT pathway is important for nitrogen assimilation. The in vitro rates of enzyme activity can however only account for about 10% of the in vivo rates of nitrogen assimilation. Nitrogen-starvation reduced GS activity to undetectable levels. On nitrate or ammonium ion refeeding the cellular GS activity was rapidly restored, and reached levels of 56% and 91% greater than the unstarved values 24h after refeeding nitrate or ammonium respectively.
平板藻 Butcher 显示出显著水平的谷氨酸合酶 (GS) (EC 2.6.1.53) 和谷氨酰胺合成酶 (GOGAT) (EC 6.3.1.2.)，但谷氨酸脱氢酶 (GDH) (EC 1.4.1.4) 的水平非常低。这表明 GS/GOGAT 途径对氮同化很重要。然而，体外酶活性的速率只能解释体内氮同化速率的大约 10%。氮饥饿使 GS 活性降低到无法检测的水平。在硝酸盐或铵离子再喂养时，细胞内 GS 活性迅速恢复，并且在再喂养硝酸盐或铵 24 小时后，分别比未饥饿的值高 56%和 91%。
