GLUTAMATE SYNTHASE AND NITROGEN ASSIMILATION

The assimilation of ammonia by a wide variety of organisms is the prim ary route for the introduction of nitrogen into the biosphere. The ass imilatory enzymes glutamine synthetase and glutamate synthase catalyze reactions that convert a-ketoglutarate and ammonia to glutamate, whic h is then used in a wide variety of biosynthetic reactions. These enzy mes also play a major role in the reassimilation of ammonia derived fr om photorespiration in C-3 plants. Recent biochemical, molecular and g enetic studies are leading to a better understanding of the factors th at determine the activity and function of glutamate synthase.