Cytokinin Utilization by Adenine-Requiring Mutants of the Yeast <i>Saccharomyces cerevisiae</i>

Kast, Carol A. Van; Laten, Howard M.

doi:10.1104/pp.83.4.726

Cited by 16 publications

(8 citation statements)

References 2 publications

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“…Since then a number of publications have reported CKX activity from a variety of tissues and species, including maize, wheat, bean, and soybean (reviewed by Armstrong 1994;Hare and Van Staden 1994a;Galuszka et al 2001). The list of organisms showing CKX activity includes two non-plant species, Dictyostelium discoideum (Armstrong and Firtel 1989) and Saccharomyces cerevisiae (Van Kast and Laten 1987). However, in our own experiments we have only detected extremely low levels of CKX activity in S. cerevisiae (Werner et al 2001) and CKXrelated sequences were not identified in Dictyostelium or Saccharomyces .…”

Section: Discovery Of Ckx Activitymentioning

confidence: 97%

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

et al. 2003

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Cytokinin oxidases/dehydrogenases (CKX) catalyze the irreversible degradation of the cytokinins isopentenyladenine, zeatin, and their ribosides in a single enzymatic step by oxidative side chain cleavage. To date the sequences of 17 fully annotated CKX genes are known, including two prokaryotic genes. The CKX gene families of Arabidopsis thaliana and rice comprise seven and at least ten members, respectively. The main features of CKX genes and proteins are summarized in this review. Individual proteins differ in their catalytic properties, their subcellular localization and their expression domains. The evolutionary development of cytokinin-catabolizing gene families and the individual properties of their members indicate an important role for the fine-tuned control of catabolism to assure proper regulation of cytokinin functions. The use of CKX genes as a tool in studies of cytokinin biology and biotechnological applications is discussed.

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Section: Discovery Of Ckx Activitymentioning

confidence: 97%

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

et al. 2003

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“…Since then, CKX has been identified and purified from many different plant species (Galuszka et al 2000). CKX-like activity has also been identified in few lower organisms, such as the moss Funaria hygrometrica (Gerhäuser and Bopp 1990), the slime mold Dictyostelium discoideum (Armstrong and Firtel 1989) and the yeast Saccharomyces cerevisiae (Van Kast and Laten 1987). The presence of endogenous CKX in D. discoideum and S. cerevisiae is however dubious, as homologous gene sequences were not found in these organisms (Schmülling et al 2003).…”

Section: Introductionmentioning

confidence: 96%

Functional expression and purification of cytokinin dehydrogenase from Arabidopsis thaliana (AtCKX2) in Saccharomyces cerevisiae

Frébortová¹,

Galuszka²,

Werner³

et al. 2007

Biologia plant.

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Cytokinin dehydrogenase (CKX) is responsible for regulating the endogenous cytokinin content by oxidative removal of the side chain and seven distinct genes, AtCKX1 to AtCKX7, code for the enzyme in Arabidopsis thaliana. The recombinant enzyme AtCKX2 was produced in Saccharomyces cerevisiae after expressing the corresponding gene from a plasmid (pDR197) or following chromosomal integration, under either the constitutive promoter PMA1 or the inducible promoter GAL1. The recombinant protein was purified from yeast culture media using a sequence of chromatographic steps. The purified enzyme had a molecular mass of 61 kDa and a typical flavoprotein spectrum. The specific activity of the enzyme was 87.8 kat g -1 , with isopentenyladenine as a substrate and 2,3-dimethoxy-5-methyl-pbenzoquinone as an electron acceptor. The pH optimum lay between 7.0 and 8.0, depending on the electron acceptor used. AtCKX2 reacts both with isoprenoid and aromatic cytokinins, the activity with isoprenoid cytokinins being two to three orders of magnitude higher. AtCKX2 prefers p-quinones and the synthetic dye 2,6-dichlorophenol indophenol as electron acceptors, although low reactivity with oxygen can also be observed. This study presents the first purification and characterization of the enzyme from Arabidopsis thaliana.Additional key words: cytokinin metabolism, cytokinin oxidase.

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“…For years, it was assumed that molecular oxygen was essential for the activity of cytokinin dehydrogenase; however, the work of Galuszka et al ( 2001 ) and Frebortova et al ( 2004 ) showed that other electron acceptors, especially quinone types such as 2,3-dimethoxy-5-methyl-1,4-benzoquinone, also functioned effi ciently other than oxygen. In addition to many plant species, the activity of this enzyme has also been reported in few lower organisms like moss, slime mold, and yeast (Gerhauser and Bopp 1990 ;Armstrong and Firtel 1989 ;Van Kast and Laten 1987 ).…”

Section: Microbial Hormonesmentioning

confidence: 95%

Plant, Soil and Microbes

2016

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Cytokinin Utilization by Adenine-Requiring Mutants of the Yeast Saccharomyces cerevisiae

Cited by 16 publications

References 2 publications

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

Functional expression and purification of cytokinin dehydrogenase from Arabidopsis thaliana (AtCKX2) in Saccharomyces cerevisiae

Plant, Soil and Microbes

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