passages.id: split_8_test_13_passage
passages.type: progene_text
passages.text: Using surface plasmon resonance , high affinity interactions were demonstrated with the regulatory subunit type I ( RIalpha ) of cAMP - dependent protein kinase ( KD = 10 nM ) and the heat - stable protein kinase inhibitor ( KD = 15 nM ) , but not with the type II regulatory subunit ( RIIalpha , KD = 2.3 microM ) under physiological conditions .