cAMP-dependent protein kinase II interactions with nuclei derived from rat mammary tumor

cAMP-dependent protein kinase from bovine heart exhibited significant interactions with nuclei from rat mammary tumors. These enzyme-nuclear interactions occurred when the intact holoenzyme was preincubated with 10 nM cAMP, 1 mM MgATP at 24 degrees C to produce high-affinity monophasic cAMP-dissociation kinetics. The enzyme-nuclear interactions are correlated with the loss of cAMP and PO4 from the purified enzyme. The data indicate that the high affinity cAMP-dependent protein kinase II exhibits significant nuclear interaction which may be related to cAMP function in rat mammary tumors.