Akimova N I, Evstigneeva Z G, Kretovich V L
Biokhimiia. 1976;41(7):1306-12.
Glutamine synthetase (GS) (E.C.6.3.1.2) activity in Chlorella cells decreased when NH4+ was added to nitrogen-free growth medium. This GS inactivation had such a rate, that it could not be due to the repression of enzyme synthesis: the GS activity decreased by 20% within 5 minutes of NH4+ assimilation. Glutamine content in cell increased in 2.5 times for this period. In vitro experiments have shown that glutamine is a strong inhibitor of GS from Chlorella grown in the presence of NO3-, and in a less degree--an inhibitor of GS from cells grown in ammonium-containing medium. The data obtained are negative with respect to possible mechanisms of GS activity regulation via adenylation and ATP-dependent destruction of glutamine synthetase.
当向无氮生长培养基中添加NH₄⁺时，小球藻细胞中的谷氨酰胺合成酶（GS）（E.C.6.3.1.2）活性降低。这种GS失活具有这样的速率，以至于它不可能是由于酶合成的抑制：在NH₄⁺同化的5分钟内，GS活性降低了20%。在此期间，细胞中的谷氨酰胺含量增加了2.5倍。体外实验表明，谷氨酰胺是在NO₃⁻存在下生长的小球藻中GS的强抑制剂，而在较小程度上是在含铵培养基中生长的细胞中GS的抑制剂。关于通过腺苷化和ATP依赖性破坏谷氨酰胺合成酶来调节GS活性的可能机制，所获得的数据是否定的。
