A near full-length cDNA copy of rat carbamoyl-phosphate synthetase I (EC 6.3.4.16) mRNA has been cloned. The cDNA insert in the recombinant plasmid pHN234 is 5.3 kilobases long. Analysis of the sequence coding for carbamoyl-phosphate synthetase I indicates that the gene has arisen from a fusion of two ancestral genes: one homologous to Escherichia coli carA, coding for a glutaminase subunit, an...

Intact avian liver mitochondria were shown to synthesize glutamine from glutamate in the absence of exogenous ATP and ammonia. With L-[U-14C]glutamate as the substrate, there was an approximate 1:1 stoichiometry between glutamate deaminated (as measured by the release of 14CO2 due to alpha-keto-[14C]glutarate oxidation) and glutamate amidated. With L-[15N]glutamate as the substrate, the isolate...

Synechocystis sp. strain PCC 6803. gene supports nitrogen assimilation in glnN cyanobacteria: the protein encoded by the A new type of glutamine synthetase in

Anthranilate synthetase was purified by ammonium sulfate precipitation and gel filtration from extracts of an episomebearing Escherichia coli mutant grown under conditions of tryptophan pathway derepression. This purification represented an l&fold increase in specific activity over the activity of the derepressedmutant extract. Starch gel electrophoresis and ultracentrifugation revealed only sl...

The moderate halophile Halobacillus halophilus is the paradigm for chloride dependent growth in prokaryotes. Recent experiments shed light on the molecular basis of the chloride dependence that is reviewed here. In the presence of moderate salinities Halobacillus halophilus mainly accumulates glutamine and glutamate to adjust turgor. The transcription of glnA2 (encoding a glutamine synthetase) ...

Previous studies have implicated glutamine synthetase (L-glutamate:ammonia ligase [adenosine diphosphate for-ing], EC 6.6.1.2) as a major controlling element of the nitrogen fixation (nif) genes in Klebsiella pneumoniae. We report here the isolation of a new class of K. pneumoniae mutants which exhibit altered patterns of nif and hut (histidine utlization) regulation. The expression of nif in t...

The synthesis of y-glutamylhydroxamic acid from glutamine and hydroxylamine is catalyzed by glutamine synthetase in the presence of adenosine diphosphate, inorganic phosphate, and magnesium ions (l), and also by other enzyme preparations (2,3) that do not exhibit a requirement for nucleotides or metal ions. The synthesis of y-glutamylhydroxamic acid from glutamic acid and hydroxylamine that is ...

Chinese milk vetch (Astragalus sinicus L.) is an important leguminous green manure that frequently suffers from seasonal drought. To improve its drought tolerance, the effects of rhizobia inoculation on tolerance and underlying physiological mechanism were investigated. Drought in combination with nitrogen assimilation, free amino acids, polyamines was investigated active nodules (AN), inactive...