This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Dixon, S. C. Articles by Mok, D. W. S. Search for Related Content PubMed PubMed Citation Articles by Dixon, S. C. Articles by Mok, D. W. S. Agricola Articles by Dixon, S. C. Articles by Mok, D. W. S.

Metabolism and Enzymology

Zeatin Glycosylation Enzymes in Phaseolus¹

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

Department of Horticulture, Oregon State University, Corvallis, Oregon 97331, Department of Chemistry, University of Bradford, Yorkshire, BD7 1DP, United Kingdom

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 (K_m 28 micromolar) but not cis-zeatin, ribosylzeatin, or dihydrozeatin. Both UDP-glucose and UDP-xylose can serve as glycosyl donors, with K_ms 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 K_ms for both zeatin and UDP-xylose are much lower (2 and 3 micromolar, respectively). The chromatographic behavior on affinity columns and molecular weights (approximate M_r 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.

This article has been cited by other articles:

				A. Cedzich, H. Stransky, B. Schulz, and W. B. Frommer Characterization of Cytokinin and Adenine Transport in Arabidopsis Cell Cultures Plant Physiology, December 1, 2008; 148(4): 1857 - 1867. [Abstract] [Full Text] [PDF]

				A. Pineda Rodo, N. Brugiere, R. Vankova, J. Malbeck, J. M. Olson, S. C. Haines, R. C. Martin, J. E. Habben, D. W. S. Mok, and M. C. Mok Over-expression of a zeatin O-glucosylation gene in maize leads to growth retardation and tasselseed formation J. Exp. Bot., July 1, 2008; 59(10): 2673 - 2686. [Abstract] [Full Text] [PDF]

				M. C. Mok, R. C. Martin, P. I. Dobrev, R. Vankova, P. S. Ho, K. Yonekura-Sakakibara, H. Sakakibara, and D. W.S. Mok Topolins and Hydroxylated Thidiazuron Derivatives Are Substrates of Cytokinin O-Glucosyltransferase with Position Specificity Related to Receptor Recognition Plant Physiology, March 1, 2005; 137(3): 1057 - 1066. [Abstract] [Full Text] [PDF]

				B. Hou, E.-K. Lim, G. S. Higgins, and D. J. Bowles N-Glucosylation of Cytokinins by Glycosyltransferases of Arabidopsis thaliana J. Biol. Chem., November 12, 2004; 279(46): 47822 - 47832. [Abstract] [Full Text] [PDF]

				M. LEXA, T. GENKOV, J. MALBECK, I. MACHACKOVA, and B. BRZOBOHATY Dynamics of Endogenous Cytokinin Pools in Tobacco Seedlings: a Modelling Approach Ann. Bot., April 1, 2003; 91(5): 585 - 597. [Abstract] [Full Text] [PDF]

				Y. K. Veach, R. C. Martin, D. W.S. Mok, J. Malbeck, R. Vankova, and M. C. Mok O-Glucosylation of cis-Zeatin in Maize. Characterization of Genes, Enzymes, and Endogenous Cytokinins Plant Physiology, March 1, 2003; 131(3): 1374 - 1380. [Abstract] [Full Text] [PDF]

				Z.-J. Xu, M. Nakajima, Y. Suzuki, and I. Yamaguchi Cloning and Characterization of the Abscisic Acid-Specific Glucosyltransferase Gene from Adzuki Bean Seedlings Plant Physiology, July 1, 2002; 129(3): 1285 - 1295. [Abstract] [Full Text] [PDF]

				G. Haberer and J. J. Kieber Cytokinins. New Insights into a Classic Phytohormone Plant Physiology, February 1, 2002; 128(2): 354 - 362. [Full Text] [PDF]

				R. C. Martin, M. C. Mok, and D. W.S. Mok A Gene Encoding the Cytokinin Enzyme Zeatin O-Xylosyltransferase of Phaseolus vulgaris Plant Physiology, June 1, 1999; 120(2): 553 - 558. [Abstract] [Full Text]

				R. C. Martin, M. C. Mok, and D. W. S. Mok Isolation of a cytokinin gene, ZOG1, encoding zeatin O-glucosyltransferase from Phaseolus lunatus PNAS, January 5, 1999; 96(1): 284 - 289. [Abstract] [Full Text] [PDF]

				R. G. Jackson, E.-K. Lim, Y. Li, M. Kowalczyk, G. Sandberg, J. Hoggett, D. A. Ashford, and D. J. Bowles Identification and Biochemical Characterization of an Arabidopsis Indole-3-acetic Acid Glucosyltransferase J. Biol. Chem., February 2, 2001; 276(6): 4350 - 4356. [Abstract] [Full Text] [PDF]

				R. C. Martin, M. C. Mok, J. E. Habben, and D. W. S. Mok A maize cytokinin gene encoding an O-glucosyltransferase specific to cis-zeatin PNAS, May 8, 2001; 98(10): 5922 - 5926. [Abstract] [Full Text] [PDF]