Multiple molecular forms of glutamine synthetase in pea seeds

Abstract

Multiple molecular forms of glutamine synthetase (GS, EC 6.3.1.2) have been studied in pea seeds of different varieties. The number of GS molecular forms in the seeds proved to be related to their colour. Two GS forms in the green seeds have been found and only one of them in the yellow seeds. Green seeds had chlorophyll content amounted to 0.4% of the total pigment content in the leaves. Chloroplasts, somewhat smaller than those in pea leaves of the same variety, have been isolated from green seeds. The presence of the second GS form in the pea green seeds we relate to the chloroplasts. By electrophoretic mobility both forms of GS from the green seeds are not identical to the chloroplast GS and the cytosol GS of leaves. Thus, we believe pea plant to contain, at least, four GS forms.

Primary structure and differential expression of glutamine synthetase genes in nodules, roots and leaves of Phaseolus vulgaris

“…However, only the R-1 gene is expressed in the nodules themselves, indicating that the R-2 gene is specifically repressed during nodule development. Key words: glutamine synthetase/gene expression/cDNA sequence/amino acid sequencelPhaseolus vulgaris GS in plants exists as a number of different isoenzymes which are associated with specific organs and cell compartments (McNally et al, 1983;Hirel and Gadal, 1980;Antonyuk et al, 1982). In Phaseolus vulgaris, two GS isoenzymes have been identified in the leaves, one in the cytosol (GS1) and the other in the chloroplast (GS2), while in root nodules two cytosolic isoenzymes were found , one of them nodule-specific (GSn-1) and the other (GSn-2) almost identical to the root form (GSr) (Lara et al, 1984).…”