Highly lipophilic phorbol esters as inhibitors of specific [3H]phorbol 12,13-dibutyrate binding.

摘要: Abstract We examined the ability of a series highly lipophilic phorbol esters to inhibit [20-3H]phorbol 12,13-dibutyrate binding cytosolic aporeceptor from mouse brain. If added in usual fashion directly into aqueous phase assay mixture, 12,13-distearate, 12,13-dioleate, and 12,13-dimyristate showed very weak inhibitory activities, with apparent inhibitor equilibrium dissociation constant values above 4 μM. In contrast, if incorporated liposomes used reconstitute aporeceptor, all three derivatives inhibited high affinities, 7.4 34 nM. The less derivative 12,13-didecanoate similar affinity, 2.4 3.2 nM, by either route addition. Consistent activity being masked an inability transfer lipid phase, 12,13-distearate efficiently (apparent constant, 14 nM) presence 0.03% Triton X-100. results suggest that ester receptor recognizes which are inserted bilayer. They indicate, moreover, low more is strongly influenced factors other than affinities.