| Phosphorylation of CaBP 1 and CaBP 2 by protein kinase CK 2 . ^^^ Serines and / or threonines in the C terminal were phosphorylated in CaBP 1 when the endogenous CK 2 was used as protein kinase . ^^^ The in vitro phosphorylation with protein kinase CK 2 can be used as a specific and sensitive method for identification of CaBP 1 , 2 , and 4 in microsomes . . ^^^ |