Ca2+/calmodulin‐dependent protein kinase in Saccharomyces cerevisiae

Abstract
Ca2+‐dependent chromatography of soluble cytosolic proteins on calmodulin‐Sepharose gave a fraction that exhibited Ca2+‐ and calmodulin‐dependent phosphorylation of several polypeptides, including 60, 56 and 45 kDa species. At 0.2 μM beef calmodulin the phosphorylation was optimal at 3 μM free Ca2+, and at 80 μM free Ca2+ it was half‐maximal at about 0.1 μM beef calmodulin. It is concluded that the fraction contains calmodulin‐dependent protein kinase(s) which is (are) autophosphorylated or associated with substrates.