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Rhodes D, Gage DA, Cooper A, et al. S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction. Plant Physiol. 1997;115(4):1541-1548doi: 10.1104/pp.115.4.1541.
Rhodes, D., Gage, D. A., Cooper, A., & Hanson, A. D. (1997). S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction. Plant physiology, 115(4), 1541-1548. https://doi.org/10.1104/pp.115.4.1541
Rhodes, D., et al. "S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction." Plant physiology vol. 115,4 (1997): 1541-1548. doi: https://doi.org/10.1104/pp.115.4.1541
Rhodes D, Gage DA, Cooper A, Hanson AD. S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction. Plant Physiol. 1997 Dec;115(4):1541-1548. doi: 10.1104/pp.115.4.1541. PMID: 12223879; PMCID: PMC158620.
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Plant Physiol. 1997 Dec;115(4):1541-1548. doi: 10.1104/pp.115.4.1541.

S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction.

Plant physiology

D. Rhodes, D. A. Gage, AJL. Cooper, A. D. Hanson

Affiliations

  1. Department of Horticulture, Purdue University, West Lafayette, Indiana 47907 (D.R.).

PMID: 12223879 PMCID: PMC158620 DOI: 10.1104/pp.115.4.1541

Abstract

Leaves of Wollastonia biflora (L.) DC. synthesize the osmoprotectant 3-dimethylsulfoniopropionate (DMSP) from methionine via S-methylmethionine (SMM) and 3-dimethylsulfoniopropionaldehyde (DMSP-ald); no other intermediates have been detected. To test whether the amino group of SMM is lost by transamination or deamination, [methyl-2H3,15N]SMM was supplied to leaf discs, and 15N-labeling of amino acids was monitored, along with synthesis of [2H3]DMSP. After short incubations more 15N was incorporated into glutamate than into other amino acids, and the 15N abundance in glutamate exceeded that in the amide group of glutamine (Gln). This is more consistent with transamination than deamination, because deamination would be predicted to give greater labeling of Gln amide N due to reassimilation, via Gln synthetase, of the 15NH4+ released. This prediction was borne out by control experiments with 15NH4Cl. The transamination product of SMM, 4-dimethylsulfonio-2-oxobutyrate (DMSOB), is expected to be extremely unstable. This was confirmed by attempting to synthesize it enzymatically from SMM using L-amino acid oxidase or Gln transaminase K and from 4-methylthio-2-oxobutyrate using methionine S-methyltransferase. In each case, the reaction product decomposed rapidly, releasing dimethylsulfide. The conversion of SMM to DMSP-ald is therefore unlikely to involve a simple transamination that generates free DMSOB. Plausible alternatives are that DMSOB is channeled within a specialized transaminase-decarboxylase complex or that it exists only as the bound intermediate of a single enzyme catalyzing an unusual transamination-decarboxylation reaction.

References

  1. J Biol Chem. 1995 Sep 22;270(38):22344-50 - PubMed
  2. Arch Biochem Biophys. 1959 Nov;85:225-33 - PubMed
  3. Plant Physiol. 1996 Aug;111(4):965-973 - PubMed
  4. Trends Biochem Sci. 1988 Nov;13(11):433-7 - PubMed
  5. Plant Physiol. 1990 Jun;93(2):623-30 - PubMed
  6. Biochemistry. 1990 Aug 21;29(33):7648-60 - PubMed
  7. J Biol Chem. 1976 Nov 10;251(21):6674-82 - PubMed
  8. Anal Biochem. 1978 Sep;89(2):451-60 - PubMed
  9. J Biol Chem. 1975 Jun 10;250(11):4029-36 - PubMed
  10. Fortschr Chem Org Naturst. 1965;23:61-112 - PubMed
  11. J Biol Chem. 1987 Jan 25;262(3):1073-80 - PubMed
  12. Plant Physiol. 1991 Feb;95(2):509-16 - PubMed
  13. Plant Physiol. 1987 Jul;84(3):775-80 - PubMed
  14. Plant Physiol. 1989 Apr;89(4):1161-71 - PubMed
  15. Plant Physiol. 1994 May;105(1):103-10 - PubMed
  16. Biochim Biophys Acta. 1995 Apr 27;1248(2):81-96 - PubMed
  17. Plant Physiol. 1997 Apr;113(4):1457-1461 - PubMed
  18. Plant Physiol. 1995 Aug;108(4):1439-48 - PubMed

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