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. 1989 Aug;90(4):1316–1321. doi: 10.1104/pp.90.4.1316

Zeatin Glycosylation Enzymes in Phaseolus1

Isolation of O-Glucosyltransferase from P. lunatus and Comparison to O-Xylosyltransferase from P. vulgaris

Susan C Dixon 1,2, Ruth C Martin 1,2, Machteld C Mok 1,2, Gordon Shaw 1,2, David W S Mok 1,2
PMCID: PMC1061889  PMID: 16666929

Abstract

An enzyme catalyzing the formation of O-glucosylzeatin in immature embryos of Phaseolus lunatus was purified 2500-fold using ammonium sulfate precipitation followed by affinity and anion exchange chromatography. The enzyme uses trans-zeatin as substrate (Km 28 micromolar) but not cis-zeatin, ribosylzeatin, or dihydrozeatin. Both UDP-glucose and UDP-xylose can serve as glycosyl donors, with Kms of 0.2 and 2.7 millimolar, respectively, for the formation of O-glucosylzeatin and O-xylosylzeatin. In comparison, the UDPxylose-zeatin:O-xylosyltransferase (JE Turner, DWS Mok, MC Mok, G Shaw [1987] Proc Natl Acad Sci USA 84: 3714-3717) isolated by the same procedures from P. vulgaris embryos uses only UDP-xylose as donor substrate and the Kms for both zeatin and UDP-xylose are much lower (2 and 3 micromolar, respectively). The chromatographic behavior on affinity columns and molecular weights (approximate Mr 44,000 daltons) of the two enzymes are similar. Results from substrate competition experiments and enzyme separation by anion exchange HPLC indicate a single, distinct, zeatin O-glycosylation enzyme occurs in embryos of each of these Phaseolus species.

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Selected References

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

  1. Chen C. M., Melitz D. K., Clough F. W. Metabolism of cytokinin: phosphoribosylation of cytokinin bases by adenine phosphoribosyltransferase from wheat germ. Arch Biochem Biophys. 1982 Apr 1;214(2):634–641. doi: 10.1016/0003-9861(82)90069-8. [DOI] [PubMed] [Google Scholar]
  2. Entsch B., Parker C. W., Letham D. S., Summons R. E. Preparation and characterization, using high-performance liquid chromatography, of an enzyme forming glucosides of cytokinins. Biochim Biophys Acta. 1979 Sep 12;570(1):124–139. doi: 10.1016/0005-2744(79)90207-9. [DOI] [PubMed] [Google Scholar]
  3. Fox J. E., Cornette J., Deleuze G., Dyson W., Giersak C., Niu P., Zapata J., McChesney J. The formation, isolation, and biological activity of a cytokinin 7-glucoside. Plant Physiol. 1973 Dec;52(6):627–632. doi: 10.1104/pp.52.6.627. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fox J. E., Sood C. K., Buckwalter B., McChesney J. D. The metabolism and biological activity of a 9-substituted cytokinin. Plant Physiol. 1971 Feb;47(2):275–281. doi: 10.1104/pp.47.2.275. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Lee Y. H., Mok M. C., Mok D. W., Griffin D. A., Shaw G. Cytokinin metabolism in phaseolus embryos : genetic difference and the occurrence of novel zeatin metabolites. Plant Physiol. 1985 Mar;77(3):635–641. doi: 10.1104/pp.77.3.635. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Mok D. W., Mok M. C. Metabolism of C-zeatin in phaseolus embryos : occurrence of o-xylosyldihydrozeatin and its ribonucleoside. Plant Physiol. 1987 Jul;84(3):596–599. doi: 10.1104/pp.84.3.596. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Mok M. C., Mok D. W., Armstrong D. J. Differential cytokinin structure-activity relationships in phaseolus. Plant Physiol. 1978 Jan;61(1):72–75. doi: 10.1104/pp.61.1.72. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Mok M. C., Mok D. W., Armstrong D. J., Rabakoarihanta A., Kim S. G. Cytokinin autonomy in tissue cultures of phaseolus: a genotype-specific and heritable trait. Genetics. 1980 Mar;94(3):675–686. doi: 10.1093/genetics/94.3.675. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Morris R. O. Mass Spectroscopic Identification of Cytokinins: Glucosyl Zeatin and Glucosyl Ribosylzeatin from Vinca rosea Crown Gall. Plant Physiol. 1977 Jun;59(6):1029–1033. doi: 10.1104/pp.59.6.1029. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Turner J. E., Mok D. W., Mok M. C., Shaw G. Isolation and partial purification of an enzyme catalyzing the formation of O-xylosylzeatin in Phaseolus vulgaris embryos. Proc Natl Acad Sci U S A. 1987 Jun;84(11):3714–3717. doi: 10.1073/pnas.84.11.3714. [DOI] [PMC free article] [PubMed] [Google Scholar]

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