[Regulation of glutamine metabolism in Chlorella pyrenoidosa. Mechanisms of regulating the activity of glutamine synthetase during ammonia assimilation].
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.
D000641:Ammonia / Q000378:metabolism*; D002708:Chlorella / Q000201:enzymology* / Q000378:metabolism; D003486:Cyanides / Q000494:pharmacology; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D005973:Glutamine / Q000494:pharmacology; D008274:Magnesium; D008345:Manganese
D003486:Cyanides; D005973:Glutamine; D008345:Manganese; D000641:Ammonia; D005974:Glutamate-Ammonia Ligase; D008274:Magnesium
Reguliatsiia metabolizma glutamina u Chlorella pyrenoidosa. Issledovanie mekhanizmov reguliatsii aktivnosti glutaminsintetazy v protsesse assimiliatsii ammoniia