Glutamine Synthetase Isoenzymes of<i>Striga hermonthica</i>and other Angiosperm Root Parasites

McNally, Sheila F.; Orebamjo, T. O.; Hirel, Bertrand; Stewart, G. R.

doi:10.1093/jxb/34.5.610

Cited by 31 publications

(17 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…GS2 always appears to be less heat stable than GS, (1,9,16,18,19). This difference in heat stability is also shown by the Chlorella isoenzymes (Fig.…”

Section: Resultssupporting

confidence: 53%

“…GS2 in higher plants is also more susceptible to inactivation by DTNB and NEM (1,16,18,19). Plant Physiol.…”

Section: Resultsmentioning

confidence: 99%

“…Ion exchange chromatography and subcellular localization studies have shown the presence of two isoenzymes in photosynthetically active tissue: GS, is localized in the cytoplasm whereas GS2 is found in chloroplasts (10,11,17). These isoenzymes differ in several respects, including their pH optima, heat stability, and Km for glutamate (1,9,16,18,19 Extracts from cells of Chlorella grown under a range of nutritional conditions were found to exhibit two peaks of glutamine synthetase activity when subjected to ion exchange chromatography (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Occurrence of Isóenzymes of Glutamine Synthetase in the Alga Chlorella kessleri

Sumar

Casselton²,

McNally³

et al. 1984

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

Recent work has shown that glutamine synthetase (EC 6.3.1.2), the key enzyme of ammonia metabolism, occurs in multiple molecular forms in many higher plants (1, 7, 12, 15, 16, 18-20, 23, 27). Ion exchange chromatography and subcellular localization studies have shown the presence of two isoenzymes in photosynthetically active tissue: GS, is localized in the cytoplasm whereas GS2 is found in chloroplasts (10,11,17). These isoenzymes differ in several respects, including their pH optima, heat stability, and Km for glutamate (1,9,16,18,19 Extracts from cells of Chlorella grown under a range of nutritional conditions were found to exhibit two peaks of glutamine synthetase activity when subjected to ion exchange chromatography (Fig. 1). The first peak eluted at 70 mm KCI and the second at 230 mm KCI, and by analogy with the corresponding chromatographic forms in higher plants they are designated GS, and GS2 (see Refs. 9 and 16). GS, was always the major form present, comprising 60 to 80% of the total activity. It is evident from the results in Figure 1 and those summarized in Table I

show abstract

“…GS2 always appears to be less heat stable than GS, (1,9,16,18,19). This difference in heat stability is also shown by the Chlorella isoenzymes (Fig.…”

Section: Resultssupporting

confidence: 53%

“…GS2 in higher plants is also more susceptible to inactivation by DTNB and NEM (1,16,18,19). Plant Physiol.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Occurrence of Isóenzymes of Glutamine Synthetase in the Alga Chlorella kessleri

Sumar

Casselton²,

McNally³

et al. 1984

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, in the present study, the smaller leaf area per stem in DS plants was a critical factor that explained its hand, there was no significant difference in nitrate reductase activity between DS and TP plants, whereas glutamine synthetase activity was 9% lower in DS than in TP plants (Table 3). Glutamine synthetase is a central enzyme in the nitrogen metabolism of higher plant (Lightfoot et al, 1988) and plays a role in the primary assimilation of ammonia (Hirel and Gadal, 1980;Tsai et al, 2003), the re-assimilation of ammonia released from the photorespiratory nitrogen cycle, and the catabolism of nitrogenous storage and transport of nitrogenous compounds (Lea and Mifl in, 2003;McNally et al, 1983). Moreover, rice plants in paddy fi elds utilize ammonium as a major nitrogen source (Ishiyama et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

Yield Component Differences between Direct-Seeded and Transplanted Super Hybrid Rice

Huang

Zou

Jiang

et al. 2011

Plant Production Science

View full text Add to dashboard Cite

“…Glutamine synthetase from barley (Hordeum distichum L.) was extracted and partially purified as described by McNally et al (14).…”

Section: Methodsmentioning

confidence: 99%

Proline and Glycine Betaine Influence Protein Solvation

Paleg¹,

Stewart²,

Bradbeer³

1984

Plant Physiol.

180

View full text Add to dashboard Cite

Glutamine synthetase from barley (Hordeum disticeaim L.) is precipitated by polyethylene glycol (PEG). Proline, in a concentration-dependent manner, reduces the amount of enzyme precipitated by PEG, although the effect of the imino acid can be counteracted by raising the level of PEG. The effect of PEG is a function of mer number and concentration and the influence of both elements can be ameliorated by proline. PEGinduced enzyme precipitation is a function of pH, as is its interaction with both proline and betaine in the reaction. The lack of effect of amount of enzyme on the proline and PEG effects supports the conclusion that, in this system, proline and PEG do not function through interaction with the protein. Other compounds, such as glycine, glucose, and sucrose, can decrease the PEG-induced precipitation of the enzyme, although glycerol was not active under the conditions employed.The results are consistent with the proposition that a protein-containing system in which high concentrations of proline and/or betaine are present, is better 'protected' against the biologically unfavorable consequences of dehydration-induced thermodynamic perturbation.The accumulation of the imino acid, proline, in the free uncombined form is a characteristic response of many plants to many types of stress (3). The interpretation of this response has varied from its description as a useful criterion for the selection of varieties suited to arid areas (27) to nothing more than a measure of the rate of senescence (9). Choosing between these extreme interpretations is difficult since plants cannot be deprived of proline, and external applications are confounded by hydration and penetration problems on the one hand, and metabolism and compartmentation of the applied compound on the other.Recent attempts to demonstrate a conceptually useful role for the accumulated proline (which may reach submaximum levels as high as 0.1-0.3 M in the wheat apex [17] or 5-10% of the dry weight of halophytic tissue [281) have centered on the amelioration of deleterious effects of heat, pH, salt, and chemicals on enzyme activity in in vitro and organelle systems (1,4,19,21,22,35). In all cases reported, significant and, indeed, important proline concentration-dependent protection against a range of perturbing or stressful conditions was afforded to several enzymes. among, if not the most prominent, and is clearly one which causes large scale proline accumulation. No in vitro system has been described with which deleterious effects of dehydration on enzyme activity can be measured, and, thus, it has not been possible to directly test the hypothesis that proline may diminish the effect of dehydration on enzymes and/or enzyme activity. Nonetheless, solvation effects do influence thermodynamic activation parameters ofenzymes (8, 13) and any component which has the ability to effect enzyme solvation may also be expected to influence enzyme activity.A system with which to test the ability of proline to effect enzyme solvation was developed from the...

show abstract

Glutamine Synthetase Isoenzymes ofStriga hermonthicaand other Angiosperm Root Parasites

Cited by 31 publications

References 20 publications

Occurrence of Isóenzymes of Glutamine Synthetase in the Alga Chlorella kessleri

Occurrence of Isóenzymes of Glutamine Synthetase in the Alga Chlorella kessleri

Yield Component Differences between Direct-Seeded and Transplanted Super Hybrid Rice

Proline and Glycine Betaine Influence Protein Solvation

Contact Info

Product

Resources

About