Altered kinetic properties of tyrosine-183 to cysteine mutation in glutamine synthetase of anabaena variabilis strain sa1 is responsible for excretion of ammonium ion produced by nitrogenase - Healy, Franklyn G.; Latorre, Charles; Albrecht, Stephan L.; Reddy, Pallavolu M.; Shanmugam, Keelnatham T. (Springer, 2003)