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Cytokinins are degraded by cytokinin oxidases (CKOs) which catalyse cleavage of the N6-(isopent-2-enyl)-side chain resulting in formation of adenine-type compounds. CKO activity has been recorded in many plants and is thought to play a key role in controlling cytokinin levels in plants. Several partially purified CKOs have been characterised but no genes(More)
Formation of the riboside-5'-monophosphate is a general feature of the metabolism of cytokinins in plants. As part of a study of the biological significance of the nucleotide form of cytokinins, we analyzed a mutant of Arabidopsis thaliana deficient in adenine phosphoribosyltransferase (APRT) activity for its ability to metabolize N(6)-benzyladenine (BA).(More)
Cytokinin oxidases (CKOs) play a major role in the regulation of hormone levels in plants by irreversibly degrading cytokinins. Two new cDNAs from maize (CKO2 and CKO3) were cloned and CKO activity of a recombinant CKO3 enzyme was demonstrated. CKO2 and CKO3 encode flavoproteins with 93% identity among each other compared with 45% identity with CKO1. The(More)
Cytokinin oxidase/dehydrogenase (CKO/CKX) is a flavoenzyme, which irreversibly inactivates cytokinins by severing the isoprenoid side chain from the adenine/adenosine moiety. There are several genes coding for the enzyme in maize (Zea mays). A Z. mays CKO1 cDNA was cloned in the yeast Yarrowia lipolytica to achieve heterologous protein expression. The(More)
In previous experiments, seven lines of valine-resistant plants were regenerated from protoplast-derived haploid tobacco mesophyll cells which had been UV mutagenized and submitted to selection by toxic concentrations of valine. In this study we described the transmission of valine-resistance to progeny and a preliminary phenotypical and biochemical(More)
BACKGROUND Limited information is available about the prevalence of the metabolic syndrome(MeTS) in India. Railway employees provided a unique opportunity to study the prevalence of MeTS in a variety of jobs. METHODS A total of 995 railway employees, 872 males (mean age 42.96 +/- 7.91) and 123 females (mean age 44.28 +/- 7.91), underwent physical(More)
Cytokinins play an important role in plant development and occur informs with different hormonal activity. As the nucleotide forms of cytokininsare considered to have little or no biological activity, the conversion ofcytokinin bases and ribosides to their nucleotides can contribute to the tuningof cytokinin activity in plant cells. Cytokinin metabolism was(More)
Cytokinins are hormones that are involved in plant growth and development. They are irreversibly degraded by cytokinin oxidases/dehydrogenases, flavoenzymes which contain a covalently bound flavine adenine dinucleotide (FAD) cofactor. Cytokinin oxidase from Zea mays (ZmCKO1) was overexpressed in the yeast Yarrowia lipolytica, purified (molecular weight 69(More)
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