[The use of pharmacological preparations for the study of calmodulin interaction with enzymes]

Calmodulin-dependent regulation of cyclic nucleotide phosphodiesterase and kinase phosphorylase activities as well as Ca2+-dependent regulation of kinase phosphorylase, mediated via the integrated calmodulin, were studied in presence of phenothiazine and butyrophenone series of pharmacological drugs. As compared with butyrophenones, phenothiazines were shown to be more effective inhibitors of calmodulin-dependent activation of the phosphodiesterase. Phenothiazines inhibited similarly the effect of calmodulin on activity of kinase phosphorylase, whereas they did not affect the Ca2+-dependent activity of kinase phosphorylase. At the same time, butyrophenones proved to inhibit the Ca2+-dependent activation of kinase phosphorylase, mediated via integrated calmodulin as well as these drugs inhibited uniformly the calmodulin-dependent regulation of both kinase phosphorylase and phosphodiesterase. The data obtained suggest that dissimilar effect of phenothiazines on calmodulin-dependent regulation of kinase phosphorylase and phosphodiesterase, carried out using dissimilar mechanisms, required an extreme caution in evaluation of physiological and biochemical experiments, where these drugs were used as means for study of calmodulin functions in biological processes.