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. 1982 Aug;70(2):353–356. doi: 10.1104/pp.70.2.353

Developmental Formation of Glutamine Synthetase in Greening Pumpkin Cotyledons and Its Subcellular Localization 1

Mikio Nishimura 1, Parichart Bhusawang 1,2, Kazimierz Strzalka 1,3, Takashi Akazawa 1
PMCID: PMC1067148  PMID: 16662494

Abstract

During the germination of pumpkin (Cucurbita sp. Amakuri Nankin) seeds in dark, the activity of glutamine synthetase in cotyledons gradually increased, reaching a maximum at 5 to 6 days. A measurable enhancement (about 4-fold) of the enzyme activity occurred when the seedlings were exposed to continuous illumination from day 4 up to day 8. Glutamine synthetase activity was detectable only in the cytosolic fraction in the etiolated cotyledons, whereas it was found both in the cytosolic and chloroplast fractions in the green cotyledons. The two isoenzymes of glutamine synthetase have been separated by DEAE-cellulose column chromatography of extracts from the green cotyledons. These data indicate that during the greening process the chloroplastic glutamine synthetase is newly synthesized. The roles of cytosolic and chloroplastic glutamine synthetase in germinating pumpkin cotyledons concerning assimilation of NH3 are discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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