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Plant Physiol. 1987 Jul;84(3):609-12. doi: 10.1104/pp.84.3.609.

Photosynthesis of Euglena gracilis under Cobalamin-Sufficient and -Limited Growing Conditions.

Plant physiology

Y Isegawa, Y Nakano, S Kitaoka

Affiliations

  1. Department of Hygiene, Kobe University School of Medicine, Chuo-ku, Kobe 650, Japan.

PMID: 16665489 PMCID: PMC1056637 DOI: 10.1104/pp.84.3.609

Abstract

Cobalamin is essential for growth of Euglena gracilis and photosynthesis. Methylcobalamin in Euglena chloroplasts (Y Isegawa, Y Nakano, S Kitaoka, 1984 Plant Physiol 76: 814-818) functions as a coenzyme of methionine synthetase. The requirement of cobalamin for photosynthesis appeared remarkably high in Euglena grown under the dark-precultured condition. The required amount of cobalamin for normal photosynthetic activity was 7.4 x 10(-11) molar, while 7.4 x 10(-10) molar cobalamin was required for normal growth. The lowered photosynthetic activity in cobalamin-limited cells was restored 20 hours after feeding cyanocobalamin or methionine to cobalamin-limited cells. Lowering of photosynthetic activity was due to loss of photosystem I activity. This photosynthetic activity was recovered after supplementation by methionine or cobalamin. The results suggest that methionine serves for the stabilization of photosystem I. This paper is the first report of the physiological function of cobalamin in chloroplasts of photosynthetic eukaryotes.

References

  1. Science. 1977 Jan 21;195(4275):301-2 - PubMed
  2. J Bacteriol. 1979 Dec;140(3):1013-6 - PubMed
  3. J Cell Biol. 1973 Jun;57(3):668-74 - PubMed
  4. Biochim Biophys Acta. 1973 Dec 14;325(3):520-9 - PubMed
  5. Biochim Biophys Acta. 1974 Apr 23;347(1):31-5 - PubMed
  6. Plant Physiol. 1984 Nov;76(3):814-8 - PubMed
  7. J Biol Chem. 1951 Nov;193(1):265-75 - PubMed
  8. J Cell Biol. 1969 May;41(2):431-40 - PubMed
  9. Plant Physiol. 1975 Sep;56(3):345-50 - PubMed
  10. Biochem Biophys Res Commun. 1963 Feb 6;10:237-42 - PubMed
  11. Plant Physiol. 1985 Mar;77(3):735-9 - PubMed

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