Glutamine synthetase regulation by energy charge in sunflower roots.

Rhythms in glutamine synthetase activity, energy charge, and glutamine in sunflower roots.

Roots of sunflower plants (Helianthus annuus L. var. Mammoth Russian) subjected to L12:D12, L18:D6, and L12:D12 followed by continuous light all display rhythms of about 12 hours for glutamine synthetase (GS) activity (transferase reaction) with one peak in the ;light phase' and one in the ;dark phase.' Root energy charge (EC = ATP+(1/2)ADP/ATP+ADP+AMP) is directly correlated with GS, but the G...

Glutamine Synthetase in Rice: A COMPARATIVE STUDY OF THE ENZYMES FROM ROOTS AND LEAVES.

Chromatographic, kinetic, and regulatory properties of glutamine synthetase in rice were investigated. By DEAE-Sephacel column chromatography, two forms (glutamine synthetase 1 and glutamine synthetase 2) were identified in leaves and one form (glutamine synthetase R) was identified in roots. Purification on hydroxyapatite and gel electrophoresis showed that glutamine synthetase R was distinct ...

Biochemical and molecular analysis of glutamine synthetase gene in brassica napus L.

Influence of ammonium and nitrate nutrition on the pyridine and adenine nucleotides of soybean and sunflower.

Total pyridine nucleotide concentration of root tissue for young soybean (Glycine max var. Bansei) and sunflower (Helianthus annuus L. var. Mammoth Russian) plants is the same with either ammonium or nitrate, but nitrate results in an increased proportion of total oxidized plus reduced NADP (NADP[H]) seemingly at the expense of NAD. The activity of NADH- and NADPH-dependent forms of glutamic ac...

The rate of CO(2) assimilation controls the expression and activity of glutamine synthetase through sugar formation in sunflower (Helianthus annuus L) leaves.

The expression and activity of glutamine synthetase (GS, EC 6.3.1.2) were examined in relation to the rate of CO2 assimilation in sunflower (Helianthus annuus L.) leaves. Intact plants were kept in the dark for 72 h and subsequently exposed to light under different atmospheric CO2 concentrations (100, 400 and 1200 microl l-1) for 6 h. The in vivo rates of net CO2 assimilation correlated with at...