Type II casein kinase (CK-2) is the only protein kinase because it can use ATP and GTP as phosphoryl donors. It is very sensitive to heparin inhibition and can be activated by polyamines and basic peptides. The peptide contains the phosphorylation sequence of CK2 and can be used as a substrate of CK2 a subunit.
Ref: Kissmehl, R. et al. FEBS Lett. 402, 18145 (1997); Hidalgo, P. Plant Physiol. 125, 396 (2001).
Sequence (One-Letter Code)
Sequence (Three-Letter Code)
H - Arg - Arg - Arg - Asp - Asp - Asp - Ser - Asp - Asp - Asp - OH