Glutamate dehydrogenase in the first leaf of wheat

Laurière, Christiane; Weisman, N. Ya.; Daussant, J.

doi:10.1111/j.1399-3054.1981.tb06049.x

Cited by 13 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the latter case, the glutamate synthase activity was also found to decrease. A rise of glutamate dehydrogenase activity aeeompanied the senescence in attached as well as in detached leaves of various plants (Barash et al 1976, Thomas 1978, Lauriere et al 1981, Cuello and Sabater 1982, Streit and Feller 1982. This behaviour of the glutamate dehydrogenase supports the present contention that this enzyme is not involved in ammonia assimilation (Miflin andLea 1980, Stewart et al 1980) but presumably more related to amino acid degradation.…”

Section: Discussionsupporting

confidence: 71%

“…For most enzymes of amino acid metabolism, including glutamate dehydrogenase, isoenzymes are known to exist (see Stewart et al 1980). The inerease of the total glutamate dehydrogenase aetivity in aging wheat leaves was shown to result from the de novo synthesis of one specific isoenzyme (Lauriere et al 1981). Irrespective of any relationships to senescence, an induction of glutamate dehydrogenase was described in response to ammonia and light in detached oat leaves (Barash et al 1974(Barash et al , 1976, and the new synthesis of a specific isoenzyme was demonstrated (Barash et al 1975).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Changes in the activities of enzymes involved in amino acid metabolism during the senescence of detached wheat leaves

Kar

Feierabend

1984

Physiologia Plantarum

View full text Add to dashboard Cite

The activities of several enzymes related to amino acid metabolism were investigated in senescing detached wheat leaves (Triticum aestivum L. cv. Diplomat) in light and darkness and after kinetin treatment. Glutamine synthetase and glutamate synthase activities rapidly declined in darkness. In light, the decline of glutamate synthase activity was retarded, while the activity of glutamine synthetase remained high and even increased transitorily. Kinetin treatment counteracted the decline of the activities of both enzymes. The activity of glutamate dehydrogenase markedly increased during senescence, particularly in light, and kinetin treatment lowered its activity. The activities of glutamate‐oxaloacetate and glutamate‐pyruvate amino‐transferases and of NADP‐dependent isocitrate dehydrogenase also increased in detached wheat leaves in light. Kinetin treatment prevented the rise of these enzyme activities. In darkness, the activities of glutamate‐oxaloacetate aminotransferase and NADP‐dependent isocitrate dehydrogenase decreased slowly while the decline of glutamate‐pyruvate aminotransferase activity was more rapid. The activity of NAD‐dependent malate dehydrogenase decreased both in light and, more rapidly, in darkness. The pattern of changes of the enzyme activities provides an explanation for the amino acid transformations and the flow of amino nitrogen into transport metabolites in senescing leaves.

show abstract

Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Changes in the activities of enzymes involved in amino acid metabolism during the senescence of detached wheat leaves

Kar

Feierabend

1984

Physiologia Plantarum

View full text Add to dashboard Cite

show abstract

“…This involves proteolytic cleavage and subsequent conversion of amino acids into compounds that can be exported from the leaf (Feller and Fischer 1994). Characteristically, some enzymes of amino acid metabolism, such as glutamate dehydrogenase (Thomas 1978, Laurière et al 1981, Loulakakis et al 1994, aspartate aminotransferase (Thomas 1978) and cytosolic glutamine synthetase (Kamachi et al 1991), that are likely to be involved in this process accumulate or persist during senescence (Ireland and Lea 1999). Enzymes not involved in this process such as chloroplastic glutamine synthetase, which is involved in ammonia reassimilation during photorespiration, decline (Peeters andvan Laere 1994, Pérez-Rodríguez andValpuesta 1996).…”

Section: Introductionmentioning

confidence: 99%

Are Isocitrate Lyase and Phosphoenolpyruvate Carboxykinase Involved in Gluconeogenesis during Senescence of Barley Leaves and Cucumber Cotyledons?

Chen¹,

Walker²,

Acheson³

et al. 2000

Plant and Cell Physiology

View full text Add to dashboard Cite

The aim of this study was to investigate whether gluconeogenesis catalysed by phosphoenolpyruvate carboxykinase (PEPCK) occurs during leaf senescence. This was addressed by determining changes in the abundance and intercellular location of enzymes necessary for gluconeogenesis during the senescence of barley leaves and cucumber cotyledons. PEPCK was never present in barley leaves, despite the presence of large amounts of isocitrate lyase (ICL), a key enzyme of the glyoxylate cycle, and of its product, glyoxylate. Although PEPCK was present in non-senescent cucumber cotyledons, its abundance declined during senescence. Throughout senescence, PEPCK was only present in the trichomes and vasculature, whereas ICL was located in mesophyll cells. Pyruvate,Pi dikinase (PPDK) which, in concert with NAD(P)-malic enzyme, is also capable of catalysing gluconeogenesis, was present in non-senescent barley leaves and cucumber cotyledons, but in both plants its abundance decreased greatly during senescence. The abundance of ICL was greatly reduced in senescing detached barley leaves by either illumination or by co-incubation with sucrose, and greatly increased in darkened attached barley leaves. These results argue against the large-scale occurrence of gluconeogenesis during senescence catalysed either by PEPCK or PPDK. In cucumber cotyledons, PEPCK may play a role in metabolic processes linked to the export of amino acids, a role in which phosphoenolpyruvate carboxylase may also be involved. The amount of ICL was increased by starvation and during senescence may function in the conversion of lipids to organic acids, which are then utilised in the mobilisation of amino acids from leaf protein.

show abstract

“…1986) and other assimilatory enzymes is associated with a transient increase in the activities of degradative enzymes (Feller and Keist 1986). In this study, GDH activity was chosen because of the known increase in activity during senescence (Thomas 1978, Cuello andSabater, 1982), which largely depends upon de novo synthesis of at least one GDH protein (Lauriere et al 1981). The results show that the typical increase in activity during senescence can be observed, and that it is most pronounced in flag leaves from plants exposed to above-ambient levels of O3.…”

Section: Discussionmentioning

confidence: 99%

Growth and leaf senescence in spring wheat (Triticum aestivum) grown at different ozone concentrations in open‐top field chambers

Grandjean

Fuhrer

1989

Physiologia Plantarum

View full text Add to dashboard Cite

J. 1989. Growth and leaf senescence in spring: wheat (Triticum aestivum) grown at different ozone concentrations in open-top field chambers. -Physiol. Plant. 77: 389-394.Spring wheat (Triticum aestivum L. cv. Albis) was grown during two consecutive seasons (1987, 1988) in open-top field fumigation chambers at a site in central Switzerland and exposed to different doses of ozone (O3) in order to study O3 effects on growth and leaf senescence. The O3 dose in nonfiltered air (NF) was 42.6 (il I"' h in 1987 and 49.2 [ill"' h in 1988. The other treatments used were: charcoal-filtered air (CF) (0.5 X O3 dose in nonfiltered air) and nonfiltered air with one of two levels of O3 added daily (0900-1700 h) (O3-I with 1.5 x O3 dose in nonfiltered air and O3-2 with L9 X O3 dose in nonfiltered air). From anthesis through senescence, dry weight of individual ears, and chlorophyll and protein content, glutamate dehydrogenase activity (GDH, EC 1.4.1.3), and the content of free and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC and MACC) in flag leaves were determined. With increasing O3 dose, the decline in chlorophyll and soluble protein contents started earlier, but the rate of decline decreased. Independent of the treatment used, GDH activity was highest during the period of maximal protein loss. With increasing O3 dose, the content of MACC increased, while that of free ACC remained unaffected. In 1988, temporal changes in MACC were related to other senescence processes. It is suggested that with increasing stress from chronic O3 exposure leaf duration is reduced, but that the pattern of senescence processes remains unchanged. OEoneinduced acceleration of flag leaf senescence could contribute to the observed reduction in ear dry weight accumulation, which may account for yield reduction in spring wheat.

show abstract

Glutamate dehydrogenase in the first leaf of wheat

Cited by 13 publications

References 8 publications

Changes in the activities of enzymes involved in amino acid metabolism during the senescence of detached wheat leaves

Changes in the activities of enzymes involved in amino acid metabolism during the senescence of detached wheat leaves

Are Isocitrate Lyase and Phosphoenolpyruvate Carboxykinase Involved in Gluconeogenesis during Senescence of Barley Leaves and Cucumber Cotyledons?

Growth and leaf senescence in spring wheat (Triticum aestivum) grown at different ozone concentrations in open‐top field chambers

Contact Info

Product

Resources

About