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Plant Physiol. 1971 Nov;48(5):580-90. doi: 10.1104/pp.48.5.580.

Generation of reduced nicotinamide adenine dinucleotide for nitrate reduction in green leaves.

Plant physiology

L Klepper, D Flesher, R H Hageman

Affiliations

  1. Department of Agronomy, University of Illinois, Urbana, Illinois 61801.

PMID: 16657841 PMCID: PMC396909 DOI: 10.1104/pp.48.5.580

Abstract

An in vivo assay of nitrate reductase activity was developed by vacuum infiltration of leaf discs or sections with a solution of 0.2 m KNO(3) (with or without phosphate buffer, pH 7.5) and incubation of the infiltrated tissue and medium under essentially anaerobic conditions in the dark. Nitrite production, for computing enzyme activity, was determined on aliquots of the incubation media, removed at intervals.By adding, separately, various metabolites of the glycolytic, pentose phosphate, and citric acid pathways to the infiltrating media, it was possible to use the in vivo assay to determine the prime source of reduced nicotinamide adenine dinucleotide (NADH) required by the cytoplasmically located NADH-specific nitrate reductase. It was concluded that sugars that migrate from the chloroplast to the cytoplasm were the prime source of energy and that the oxidation of glyceraldehyde 3-phosphate was ultimately the in vivo source of NADH for nitrate reduction.THIS CONCLUSION WAS SUPPORTED BY EXPERIMENTS THAT INCLUDED: inhibition studies with iodoacetate; in vitro studies that established the presence and functionality of the requisite enzymes; and studies showing the effect of light (photosynthate) and exogenous carbohydrate on loss of endogenous nitrate from plant tissue.The level of nitrate reductase activity obtained with the in vitro assay is higher (2.5- to 20-fold) than with the in vivo assay for most plant species. The work done to date would indicate that the in vivo assays are proportional to the in vitro assays with respect to ranking genotypes for nitrate-reducing potential of a given species. The in vivo assay is especially useful in studying nitrate assimilation in species like giant ragweed from which only traces of active nitrate reductase can be extracted.

References

  1. Biochim Biophys Acta. 1968 Jan 15;153(1):211-8 - PubMed
  2. Bacteriol Rev. 1961 Mar;25(1):32-48 - PubMed
  3. Plant Physiol. 1960 Sep;35(5):700-8 - PubMed
  4. Plant Physiol. 1965 Jul;40(4):691-8 - PubMed
  5. Biochem J. 1962 Mar;82:554-60 - PubMed
  6. Biochem Biophys Res Commun. 1967 Jan 10;26(1):14-7 - PubMed
  7. Arch Biochem Biophys. 1951 Jun;32(1):158-69 - PubMed
  8. Biochim Biophys Acta. 1964 Sep 18;89:453-64 - PubMed
  9. Plant Physiol. 1969 Jan;44(1):110-4 - PubMed
  10. Plant Physiol. 1970 Jul;46(1):45-9 - PubMed
  11. Biochim Biophys Acta. 1965 Nov 29;109(2):390-408 - PubMed
  12. Plant Physiol. 1964 May;39(3):416-22 - PubMed
  13. Plant Physiol. 1959 Jul;34(4):396-400 - PubMed
  14. Plant Physiol. 1968 Jun;43(6):930-40 - PubMed
  15. Plant Physiol. 1963 May;38(3):355-60 - PubMed
  16. Biochim Biophys Acta. 1964 Feb 10;82:313-24 - PubMed
  17. Proc Natl Acad Sci U S A. 1970 Mar;65(3):729-36 - PubMed
  18. Plant Physiol. 1967 Feb;42(2):233-7 - PubMed
  19. Annu Rev Biochem. 1970;39:389-428 - PubMed
  20. J Biol Chem. 1965 Dec;240(12):4603-8 - PubMed
  21. Plant Physiol. 1965 Nov;40(6):1013-22 - PubMed

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