Quantification of Mesotaenium Calmodulin by Improved Cyclic Nucleotide Phosphodiesterase Test
Calmodulin alike actin and a few other eukaryotic polypeptides is a highly conserved protein expressed in animal and plant cells (Cheung, 1970; Marme and Dieter, 1983). Thus, despite its plant source, calmodulin from the green algae Chlamydomonas and Mougeotia, from fungi including Dictyostelium and Neurospora, from the moss Funaria and from a large set of higher plants (Marme and Dieter, 1983) was found to active bovine heart cyclic nucleotide phosphodiesterase in a calcium-dependent manner much the same as bovine calmodulin does. Other remarkable properties of calmodulin, although of minor distinctive strength, are heat stability, Ca2+-dependent high affinity binding to antipsychotic drugs including chlorpromazine and fluphenazine, and Ca2+-dependent electrophoretic mobility in sodium-dodecyl-sulfate polyacrylamide gels. Thus, the cyclic nucleotide phosphodiesterase test has turned out the major functional tool of calmodulin identification. The cyclic nucleotide phosphodiesterase test, however, as run so far (Cheung, 1969), appears lengthy and tedious with more than 15 individual steps of sample processing including multiple transfers of sample aliquots, protein denaturation and sample centrifugation.