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Regulation of glutamine synthetase ec 6.3.1.2 in the blue green alga anabaena l 31






Biochimica et Biophysica Acta 613(2): 526-533

Regulation of glutamine synthetase ec 6.3.1.2 in the blue green alga anabaena l 31

In N2-grown cultures of Anabaena L-31, in which protein synthesis was prevented by chloramphenicol, presence of NH4+ caused a drastic decrease of glutamine synthetase (L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2) activity indicating NH4+-mediated inactivation or degradation of the enzyme. The half-life of glutamine synthetase was more than 24 h, while that of nitrogenase (reduced ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing), EC 1.18.2.1) was less than 4 h, suggesting that glutamine synthetase may not act as positive regulator of nitrogenase synthesis in Anabaena. Glutamine synthetase purified to homogeneity was subject to cumulative inhibition by alanine, serine and glycine. The amino acids, however, exhibited partial antagonism in this behavior. Glyoxylate, an intermediate in photorespiration, virtually prevented the amino acid inhibition. Kinetic studies revealed inhibition of the enzyme activity by high Mg2+ concentration under limiting glutamate level and by high glutamate in limiting Mg2+. Maximum enzyme activity occurred when the ratio of glutamate to free Mg2+ was 0.5 to 1.0. The results demonstrate that the enzyme is subject to multiple regulation by various metabolites involved in N assimilation.


Accession: 006288134



Related references

Tuli, R.; Thomas, J., 1980: Regulation of glutamine synthetase in the blue-green alga Anabaena L-31. In N2-grown cultures of Anabaena L-31, in which protein synthesis was prevented by chloramphenicol, presence of NH+4 caused a drastic decrease of glutamine synthetase (L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2) activity indicating NH+4-...

Mcmaster, B.J.; Danton, M.S.; Storch, T.A.; Dunham, V.L., 1980: Regulation of glutamine synthetase ec 6.3.1.2 in the blue green alga anabaena flos aquae. Glutamine synthetase (GS) was isolated from log phase cells and purified to a single protein as evidenced by gel electrophoresis. Protamine and ammonium sulfate precipitation and chromatography on DEAE-cellulose and Bio-Gel resulted in 380-fold pu...

McMaster, B.J.; Danton, M.S.; Storch, T.A.; Dunham, V.L., 1980: Regulation of glutamine synthetase in the blue-green alga Anabaena flos-aquae. Glutamine synthetase (GS) was isolated from log phase cells and purified to a single protein as evidenced by gel electrophoresis. Protamine and ammonium sulfate precipitation and chromatography on DEAE-cellulose and Bio-Gel resulted in 380-fold pu...

Rowell, P.E.ticott, S.S.ewart, W., 1977: Glutamine synthetase and nitrogenase activity in the blue green alga Anabaena cylindrica. New phytologist: 79 (1) 41-54

Rowell, P.; Enticott, S.; Stewart, W.D.P., 1977: Glutamine synthetase ec 6.3.1.2 and nitrogenase activity in the blue green alga anabaena cylindrica. On adding NH4+ to N-fixing cultures of A. cylindrica, the glutamine pool of the intact filament increases within seconds. Nitrogenase activity and then glutamine synthetase [EC 6.3.1.2] activity decline. There are no changes in the activities of g...

Tuli, R.; Jawali, N.; Thomas, J., 1979: A rapid method for the purification of glutamine synthetase ec 6.3.1.2 from the blue green alga anabaena l 31. Glutamine synthetase from Anabaena L-31 was purified to homogeneity by a 2-step procedure involving ammonium sulphate precipitation and affinity chromatography on blue Sepharose. The high recovery, convenience and rapidity of the procedure qualify...

Tuli, R.J.wali, N.T.omas, J., 1979: A rapid method for the purification of glutamine synthetase from the blue-green alga Anabaena L-31. Indian journal of experimental biology 17(11): 1239-1241

Orr, J.H.selkorn, R., 1982: Regulation of glutamine synthetase activity and synthesis in free-living and symbiotic Anabaena spp. Cyanobacteria, blue-green algae. Journal of bacteriology 152(2): 626-635

Ohmori, M.S.ino, T.O.mori, K., 1985: Occurrence of glutamine-2-oxoacid transaminase activity in the blue-green alga Anabaena gylindrica. Journal of general and applied microbiology1(2): 171-176

Ohmori M.; Saino T.; Ohmori K., 1985: Occurrence of glutamine 2 oxoacid transaminase activity in the blue green alga anabaena cylindrica. Asparate and glutamate were formed from glutamine and oxaloacetate with crude enzyme extracts obtained by ammonium sulfate precipitation (35-65% saturation) from the blue-green alga Anabaena cylindrica. In this reaction the 2-amino group of glutam...