The change in glutamine synthetase activity has been studied under two conditions of liver growth, namely, mitotic growth after partial hepatectomy and nonmitotic growth during repletion after a fast. The surgical operation caused the enzyme activity in the liver to diminish to one half its normal value within one week after the operation and to remain at this reduced level for the duration of ...

Mixed-function oxidation of glutamine synthetase from Escherichia coli causes loss of catalytic activity. The inactivation correlates with the loss of 1 of 16 histidine residues/subunit (Levine, R.L. (1983) J. Biol. Chem. 258, 11823-11827). A cyanogen bromide peptide containing the oxidizable histidine has been isolated. Within the protein, the sequence is Met-His-Cys-His-Met. This hydrophilic ...

We studied the effects of oral administration of RU38486, a potent and selective glucocorticoid antagonist, on muscle weight, non-collagen protein content, and selected enzyme activities (choline acetyltransferase, glucose-6-phosphate dehydrogenase, and glutamine synthetase) following denervation of rat skeletal muscle. Neither decreases in muscle weight, protein content, and choline acetyltran...

Pathways of ammonia assimilation into glutamic acid in Bacillus azotofixans, a recently characterized nitrogen-fixing species of Bacillus, were investigated through observation by NMR spectroscopy of in vivo incorporation of 15N into glutamine and glutamic acid in the absence and presence of inhibitors of ammonia-assimilating enzymes, in combination with measurements of the specific activities ...

Rhodopseudomonas palustris, Glutamine Synthetase Regulation, Adenylylation Glutamine synthetase from Rhodopseudomonas palustris is regulated via an adenylylation/ deadenylylation mechanism. The enzyme purified from ammonia-grown cells, released AMP upon treatment with phosphodiesterase, along with drastic changes in its pH and metal dependency. Kinetic parameters for enzyme-substrate interactio...

The formation of amidase was studied in mutants from Pseudomonas aeruginosa PAO lacking glutamine synthetase activity. It appeared that catabolite repression of amidase synthesis by succinate was partially relieved when cellular growth was limited by glutamine. Under these conditions, a correlation between amidase and urease formation was observed. The results suggest that amidase formation in ...

GLUTAMINE synthetase [L-glutamate-ammonia ligase (ADP)] (EC 6.3.1.2) of rat cerebral cortex may be readily inhibited by the convulsant agent dl-methionine-di-sulfoximine (MSO), both in vitro and in vivo. 1, 8 Although in vitro this inhibition is readily reversible by excess substrate, L-glutamate, the inhibition in vivo appears to reflect a nonreversible interaction of the convulsant drug with ...

The anthranilate aggregate, which catalyzes the first two reactions of tryptophan biosynthesis in Escherichia coli, consists of two anthranilate synthetase subunits and two phosphoribosyltransferase subunits. The aggregate remains associated under physiological conditions. Three lines of evidence indicate that regulation in the aggregate involves conformational changes associated with the bindi...

Carbamoyl phosphate synthetase from Escherichia coli catalyzes the formation of carbamoyl phosphate from ATP, bicarbonate, and glutamine. The amidotransferase activity of this enzyme is catalyzed by the smaller of the two subunits of the heterodimeric protein. The roles of four conserved histidine residues within this subunit were probed by site-directed mutagenesis to asparagine. The catalytic...

ffects of L-asparagine and L-glutamine on growth, pigments content and metabolism of haseolus vulgaris plants, at two stages of plant growth and development in was investigated in icropropagated tissues (in vitro). In general, all growth parameters increased by 1 & 2 mM sparagine or glutamine treatments while decreased in response to other concentrations (3, 4 & 5 M), Similarly total carbohydra...