Fusicoccin structure-activity relationships: In vitro binding to microsomal preparations of maize coleoptiles [cotylenins, receptors]
1981
Ballio, A. | Federico, R. | Scalorbi, D. (Rome Univ. (Italy). Istituto de Chimica Biologica)
The ability of a number of fusicoccin (FC) derivatives and analogues to compete with tritiated dihydro-FC in a binding test to microsomal preparations of maize (Zea mays L. variety XL 342) coleoptiles has been investigated. The binding affinity of each compound, expressed as the concentration of unlabeled ligand at which the maximum specific binding of labeled dihydro-FC is displaced by 50% (IC(,50)), has allowed to quantitate structure-activity relationships by this test. The results largely confirm previous data of in vivo assays, and show that a. the role of the glucose moiety is only secondary to that of the aglycone, b. an unsubstituted OH on C-8 and the configuration at C-3 and C-9 are imported for an efficient binding, the conformation of the 8-membered ring probably affects the interaction with the FC-binding sites.
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