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Anticytokinins

We have developed recently a couple of classes of anticytokinins which antagonizes the effect of cytokinins 47,48). The anticytokinin activity of N4-substituted 4-amino-... [Pg.143]

The optimum B4 value for N4-substituents, 4.5 A coincides very well not only with that for N substituents of adenylate cytokinins, 5.2 A, shown in the previous section, but also with the value of 4.7 A observed for another class of compounds, N4-substituted 4-amino-2-methylpyrrolo[2,3-d]pyrimidines (24)47) which show either cytokinin or anticytokinin activity depending upon the structure of N4-substituents. These results in combination may help to think of the size of structure which should sterically fit well the cytokinin receptor cavity. [Pg.143]

The variation of the activity from agonistic to antagonistic in the pyrrolo[2,3-d]-pyrimidine derivatives is consecutive in terms of structure and well elucidated by the B4 value of the N4-substituents 47). The B4 value within a range of 4.7-6.0 yields agonists, whereas that outside this range leads to anticytokinins. Steric dimensions of compounds are important factor determining the type of the activity as well as the potency. [Pg.144]

Compound 14, having the structural and growth-promoting characteristics expected of a potential anticytokinin, was tested for its ability to block the promotion of cell division and growth by other compounds having significant cytokinin activity. [Pg.84]

The accumulated assay results obtained with the 4-alkyl-2-methylpyrrolo[2,3-d]pyrimidines are of special interest. Can-pounds 25 and 26 exhibited significant cytokinin activity in all assays utilized. On the other hand, compound 27 was a potent antagonist in the tobacco bioassay but had little activity in the other two assay systems, while 29 acted as an anticytokinin in the tobacco bioassay and a cytokinin in the lettuce seed germination assay, but was without activity in the Amaranthus test system. [Pg.92]

Anticytokinins Elicit Responses in Several Plant Bioassays... [Pg.94]

Since the discovery of cytokinins, different adenylate and non-adenylate compounds have been synthesized and classified as potent anticytokinins based on the reduction of cytokinin effects, i.e. chlorophyll retention, radish leaf expansion and callus growth. [Pg.207]

Most of the cytokinin antagonists were identified based on their biological effect in various cytokinin bioassays. From structure-activity relationship studies and inhibitor-like effects, it was hypothesized that these compounds act as competitive inhibitors at the receptor level [28,31,32]. However, direct proof that the molecular target of these compounds is the cytokinin receptor has been hindered by the dearth of knowledge of cytokinin receptors and signaling. After the cytokinin receptors have been identified in Arabidopsis and maize [38-40], the mode of action of the above described types of anticytokinins can be revised. Our recent results show that the molecular target of some of the potent pyrimidine-derived anticytokinins is not the cytokinin receptor, but rather cell-division machinery (L, Spichal, unpublished). [Pg.207]

Anticytokinins agents that partially negate the physiological effects of cytokinins, e.g. the synthetic kinetin inhibitor, 6-methylpurine. [Pg.45]

Structure-Activity Relationship Studies and Development of 5-li iazine and Carbamate Anticytokinins... [Pg.179]


See other pages where Anticytokinins is mentioned: [Pg.119]    [Pg.143]    [Pg.143]    [Pg.79]    [Pg.81]    [Pg.83]    [Pg.83]    [Pg.83]    [Pg.84]    [Pg.85]    [Pg.86]    [Pg.86]    [Pg.86]    [Pg.86]    [Pg.87]    [Pg.92]    [Pg.92]    [Pg.93]    [Pg.94]    [Pg.94]    [Pg.95]    [Pg.97]    [Pg.233]    [Pg.207]    [Pg.233]    [Pg.97]    [Pg.207]    [Pg.179]    [Pg.179]    [Pg.179]    [Pg.180]    [Pg.180]    [Pg.180]    [Pg.181]    [Pg.181]   
See also in sourсe #XX -- [ Pg.207 ]

See also in sourсe #XX -- [ Pg.207 ]

See also in sourсe #XX -- [ Pg.179 , Pg.180 , Pg.181 , Pg.182 , Pg.183 , Pg.184 ]




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Adenylate anticytokinins

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