Glutamine synthetase (GS) mainly exists in plants, is one of the key enzymes of ammonia assimilation in
organism, which can catalytic synthesis of glutamine by ammonium ion and glutamic acid. The synthesis
of glutamine not only prevents excessive ammonium ions from being toxic to organisms, but glutamine is
also the main storage and transport form of ammonia.
GS catalyzes the synthesis of glutamine from ammonium and glutamic acid in the presence of ATP and
Mg2+. Glutamine is further converted to gamma-glutamyl hydroxamic acid, which can form a red complex
with iron under acidic condition. This complex has a maximum absorption peak at 540 nm.
Reagents and Equipment Required but Not Provided:
Spectrophotometer/microplate reader, water bath, desk centrifuge, adjustable pipette, micro glass
cuvette/96 well flat-bottom plate, mortar/homogenizer, ice and distilled water.
