Calcium and calmodulin-dependent phosphorylation of kappa-casein by a bovine mammary casein kinase.
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 microM 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.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology*; D047388:Casein Kinases; D002364:Caseins / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D007774:Lactation / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D011247:Pregnancy; D011494:Protein Kinases / Q000378:metabolism*
D002147:Calmodulin; D002364:Caseins; D011494:Protein Kinases; D047388:Casein Kinases; D002118:Calcium