摘要：

Conformational changes play an important role in the function of proteins. Glutamine synthetase, an important enzyme of nitrogen metabolism, was purified under sporulating (GSala) and non-sporulating (GSpyr) conditions and the effect of Mg on these multiple forms was studied by fluorescence spectroscopy to detect possible conformational changes that occur in the presenceof Mg. The substantial changes in the fluorescence emission maximum, fluorescence intensity and lifetime that occur in the presence of different concentrations of Mg, indicated major changes in molecular conformations in both forms of this enzyme. The fluorescent changes produced by the effect of Mg in GSala was much more prominent than in GSpyr. These observations strongly support the possibility that GSala and GSpyr undergoes a conformational change on binding with Mg.

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