Study On Isoenzyme Of Glutamine Synthetase In Tobacco

GS is the key enzyme participating in the process of ammonium assimilation in higher plants. In the root of tobacco, GS activity exists in the cytosol of root specifically, while there are different standpoints about the kind of GS in the leaves. Recently,it is considered that only one or two GS isoenzymes exists in the tobacco leaves. Whether in the presence of several tobacco GS isozyme, since there is no clear documentation. .Generally speaking, GS in plant mainly assimilates the inorganic nitrogen in the process of nitrogen metabolism, but it cannot show the special function and intricate response to external environment of GS, especially its many isoenzyme. In the base of advance on the function of glutamic acid and its acceptor in plant signal transduction, not less than six active bands were observed in the root of tobacco in the way of Native-PAGE and Western blot. The hypotheses that nine kinds of GS isoenzyme exist in the root of tobacco was put forward, and explore the role of light source and measures on tobacco topping to GS isozyme, the light is created by dark red membrane. Changing the quality of light so that decrease the activity of GSr1-3 of roots of tobacco.and increase activity of GSr1-4. topping 24 hours later, activity of GSr2 Significantly reduced and almost disappeared. Topping 240 hours later, the it restored the state of nearly topping. The total activity of GS results as: the change of GSr2 and the total activity of GS of tobacco roots is not consistent. On the Basis ofPlant glutamate and glutamate receptors in the role of plant signal transduction research in progress , We came to the conclusion that GS isoenzyme has more role besides metabolism effect . According to the above mentioned analysis, this paper explained the possible role of the Glutamine synthetase on the signal transduction process in the nitrogen metabolism of plant to development.