PMID: 16661701Mar 1, 1981

Metabolism of Cytokinin : DEPHOSPHORYLATION OF CYTOKININ RIBONUCLEOTIDE BY 5'-NUCLEOTIDASES FROM WHEAT GERM CYTOSOL

Plant Physiology
C M Chen, S M Kristopeit

Abstract

Two forms (F-I and F-II) of 5'-nucleotidases (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) which catalyze the dephosphorylation of N(6)-(Delta(2)-isopentenyl)adenosine 5'-monophosphate and AMP to form the corresponding nucleosides were partially purified from the cytosol of wheat (Triticum aestivum) germ. Both the F-I (molecular weight, 57,000) and F-II (molecular weight, 110,000) 5'-nucleotidases dephosphorylate the ribonucleotides at an optimum pH of 7. The K(m) values for the cytokinin nucleotide are 3.5 micromolar (F-I enzyme) and 12.8 micromolar (F-II enzyme) in 100 millimolar Tris-maleate buffer (pH 7) at 37 C. The F-I enzyme is less rapidly inactivated by heating than is the F-II enzyme. Both nucleotidases hydrolyze purine ribonucleoside 5'-phosphates, AMP being the preferred substrate. N(6)-(Delta(2)-isopentenyl)Adenosine 5'-monophosphate is hydrolyzed at a rate 72 and 86% that of AMP by the F-I and F-II nucleotides, respectively. Phenylphosphate and 3'-AMP are not substrates for the enzymes. It is proposed that dephosphorylation of cytokinin nucleotide by cytosol 5'-nucleotidases may play an important role in regulating levels of "active cytokinin" in plant cells.

References

Feb 16, 2011·Journal of Experimental Botany·Ivo FrébortPetr Galuszka
Mar 1, 1990·Plant Physiology·W M Van der KriekenG J Wullems
May 5, 2001·Annual Review of Plant Physiology and Plant Molecular Biology·David WS Mok, Machteld C Mok
Jan 28, 2014·The Arabidopsis Book·Joseph J Kieber, G Eric Schaller
Sep 8, 2016·Frontiers in Plant Science·Mária ŠmehilováPetr Galuszka
Sep 8, 2016·Plant Physiology and Biochemistry : PPB·Marta GietlerBarbara Zagdańska
Jan 17, 2004·The Journal of Biological Chemistry·Hiroyuki KasaharaHitoshi Sakakibara
Feb 9, 2007·Nature·Takashi KurakawaJunko Kyozuka
Jan 16, 2010·Journal of Integrative Plant Biology·Toru KudoHitoshi Sakakibara
Nov 9, 2011·The Plant Journal : for Cell and Molecular Biology·Hiroki TokunagaHitoshi Sakakibara

Citations

May 30, 1978·Biochemical and Biophysical Research Communications·J DornandJ C Mani
Oct 16, 1978·Biochemical and Biophysical Research Communications·W J Burrows
Jan 18, 1972·Biochemistry·W B Gibson, G I Drummond
Jul 3, 1972·Biochimica Et Biophysica Acta·C M Huang, T W Keenan
Mar 1, 1973·Proceedings of the National Academy of Sciences of the United States of America·J W Einset, F Skoog
Mar 1, 1977·Plant Physiology·C M Chen, R L Eckert
Dec 1, 1978·Plant Physiology·C M Chen, B Petschow

Related Concepts

Metabolic Process, Cellular
Ribonucleotides
Nucleotidases
Nebularine
Enzymes, antithrombotic
5 Prime Nucleotidase Measurement
Tromethamine
Wheat germ preparation
Maleate
Metabolic Pathway

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