Abstract
A calcium and calmodulin-dependent .kappa.-casein kinase activity has been described in the bovine mammary gland. This kinase required previously dephosphorylated .kappa.-casein for substrate, thus suggesting a physiological role for this enzyme. The .kappa.-casein kinase required magnesium and the presence of both calcium and calmodulin for full activity. Calmodulin concentrations of .32 .mu.M achieved one-half maximal activation of this enzyme. The calcium and calmodulin-dependent .kappa.-casein kinase was found in preparations of mammary acini and could be localized in a membranous fraction by centrifugation. The particles containing this activity had a high density (1,309 g/cc) and cofractionated with caseins, suggesting this enzyme may be present in secretory granules.

This publication has 37 references indexed in Scilit: