Cytosolic glutamine synthetase in higher plants.

Cytosolic glutamine synthetase (GS₁) was purified to homogeneity from etiolated barley leaves by DEAE-Sephacci and hydroxyapatite chromatography, gel filtration and polyacrylamide get electrophoresis. Specific antibodies against the purified protein were raised by the immunization of rabbits. Immunoprecipitation experiments demonstrated that cytosolic glut a mine synthetases isolated from the leaves of different plant species were very similar proteins. Good recognition of other cytosolic glutamine synthetases from roots, root nodular tissue and seeds by barley GS₁ antibodies was obtained, suggesting that they too are all quite similar proteins In contrast, chloroplast glut amine synthetase (GS₂) was considered to be a different protein in view of its low level of recognition by barley GS₁ antibodies. [ABSTRACT FROM AUTHOR]