Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1986 Jul;81(3):754–757. doi: 10.1104/pp.81.3.754

Synthesis of [15N]Glutamate from [15N]H4+ and [15N]Glycine by Mitochondria Isolated from Pea and Corn Shoots 1

Tomoyuki Yamaya 1,2,3, Ann Oaks 1,2,3, David Rhodes 1,2,3, Hideaki Matsumoto 1,2,3
PMCID: PMC1075421  PMID: 16664897

Abstract

Metabolically competent mitochondria were isolated from pea and corn shoots on Percoll discontinuous density gradients. Rates of synthesis of [15N]glutamate were measured by gas chromatography-mass spectrometry after the incubation of mitochondria with either 2 millimolar [15N] H4+ or [15N]glycine in the presence of 1 millimolar citrate as the respiratory substrate. When [15N]H4+ was provided, mitochondria isolated from light-grown pea shoots synthesized [15N]glutamate with a rate of 2.64 nanomoles per hour per milligram mitochondrial protein. Corn mitochondria produced [15N]glutamate at a rate approximately 11 times greater than the pea mitochondria. Dark treatment during growth for the last 24 hours caused a slight reduction in the rate of synthesis in both species. When [15N]glycine was used, pea mitochondria synthesized [15N]glutamate with a rate of 6.32 nanomoles per hour per milligram protein. Rapid disappearance of [15N]glycine and synthesis of [15N]serine was observed with a molar ratio of 2 glycine to 0.78 serine. The rate of glutamate synthesis was only 0.2% that of serine, due in part to the dilution of [15N]H4+ by the [14N]H4+ pool in the mitochondria. The majority of the [15N]H4+ released from glycine appears to have been released from or remains unmetabolized in the mitochondria. Corn mitochondria showed no apparent disappearance of [15N]glycine and little synthesis of [15N]serine, indicating that our preparation originated primarily from mesophyll cells. Under our conditions of glycine/serine conversion, [15N]glutatmate was synthesized at a rate of 7% of that of [15N]serine synthesis by corn mitochondria.

Full text

PDF
754

Selected References

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

  1. Martin F., Winspear M. J., Macfarlane J. D., Oaks A. Effect of Methionine Sulfoximine on the Accumulation of Ammonia in C(3) and C(4) Leaves : The Relationship between NH(3) Accumulation and Photorespiratory Activity. Plant Physiol. 1983 Jan;71(1):177–181. doi: 10.1104/pp.71.1.177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. McNally S. F., Hirel B., Gadal P., Mann A. F., Stewart G. R. Glutamine Synthetases of Higher Plants : Evidence for a Specific Isoform Content Related to Their Possible Physiological Role and Their Compartmentation within the Leaf. Plant Physiol. 1983 May;72(1):22–25. doi: 10.1104/pp.72.1.22. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Moore R., Black C. C. Nitrogen Assimilation Pathways in Leaf Mesophyll and Bundle Sheath Cells of C(4) Photosynthesis Plants Formulated from Comparative Studies with Digitaria sanguinalis (L.) Scop. Plant Physiol. 1979 Aug;64(2):309–313. doi: 10.1104/pp.64.2.309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Neeman M., Aviv D., Degani H., Galun E. Glucose and glycine metabolism in regenerating tobacco protoplasts: followed nondestructively by nuclear magnetic resonance spectroscopy. Plant Physiol. 1985 Feb;77(2):374–378. doi: 10.1104/pp.77.2.374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Rathnam C. K., Edwards G. E. Distribution of Nitrate-assimilating Enzymes between Mesophyll Protoplasts and Bundle Sheath Cells in Leaves of Three Groups of C(4) Plants. Plant Physiol. 1976 Jun;57(6):881–885. doi: 10.1104/pp.57.6.881. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Rhodes D., Myers A. C., Jamieson G. Gas Chromatography-Mass Spectrometry of N- Heptafluorobutyryl Isobutyl Esters of Amino Acids in the Analysis of the Kinetics of [N]H(4) Assimilation in Lemna minor L. Plant Physiol. 1981 Nov;68(5):1197–1205. doi: 10.1104/pp.68.5.1197. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Sarojini G., Oliver D. J. Inhibition of glycine oxidation by carboxymethoxylamine, methoxylamine, and acethydrazide. Plant Physiol. 1985 Mar;77(3):786–789. doi: 10.1104/pp.77.3.786. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Walker K. A., Givan C. V., Keys A. J. Glutamic Acid metabolism and the photorespiratory nitrogen cycle in wheat leaves: metabolic consequences of elevated ammonia concentrations and of blocking ammonia assimilation. Plant Physiol. 1984 May;75(1):60–66. doi: 10.1104/pp.75.1.60. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Yamaya T., Oaks A., Matsumoto H. Characteristics of glutamate dehydrogenase in mitochondria prepared from corn shoots. Plant Physiol. 1984 Dec;76(4):1009–1013. doi: 10.1104/pp.76.4.1009. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Yamaya T., Oaks A., Matsumoto H. Stimulation of Mitochondrial Calcium Uptake by Light during Growth of Corn Shoots. Plant Physiol. 1984 Jul;75(3):773–777. doi: 10.1104/pp.75.3.773. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES