Heterogeneity of glutamine synthetase polypeptides in Neurospora crassa.

Purified preparations of Neurospora crassa glutamine synthetase contain two nonidentical polypeptides that can be separated by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and 7 M urea. These polypeptides are synthesized both in vivo and in a heterologous cell-free protein-synthesizing system. The data presented indicate that both polypeptides contain an active site for glutamine synthetase activity and suggest that there is not a precursor-product relationship between them.